Magic: The Gathering Arena

Abilities:

• ANNIHILATOR: Keyword ability found only on "Kozilek, Butcher of Truth" in this game. When the Annihilator creature attacks, the opponent sacrifices permanents of their choosing equal to the creature's annihilator value.
• BEATSTICK: Slang term for any creature that's a good attacker, often meaning high attack power or good abilities. Terra Stomper has Trample and is an 8/8, ensuring that whenever it attacks, it's likely to do some damage.
• BLOODRUSH: Keyword ability. Paying a creature's Bloodrush cost discards the card and bestows its ability to another target creature. Wrecking Ogre's Bloodrush grants +3/+3 and double strike to a specified attacker. The Bloodrush cost tends to be more stringent than if one had played the creature normally.
• BOUNCING: The term for returning cards on the field to its owner's hand or library. Cards that are bounced lose all counters placed on them, and this isn't a "destroy" effect, so it can affect indestructible creatures.
• CASCADE: An enemy-only keyword ability. When a spell with Cascade plays out, its owner picks up cards from the top of their deck until they find a nonland permanent with a CMC lower than the Cascade's. The chosen card is played cost-free; the other cards picked up are put on the library's bottom.
• CMC (CONVERTED MANA COST): The cost of a card taken as whole. For instance, a Soul of Zendikar costs 4 colorless mana and 2 green mana, so its CMC would be 6 (4+2). Cards with a variable mana amount of "X" are considered "0" for CMC calculation. Genesis Hydra is 2 green mana + "X" colorless mana, where "X" can be any applicable number. Its CMC is simply 2.
• CONVOKE: Keyword ability. Cards with Convoke cost 1 mana less to cost for each creature its player taps while it enters. If a creature shares a color with the Convoke card, it can count as that color's mana instead of just a colorless mana. Meditation Puzzle costs 3 + 2 white mana (CMC 5). It effectively costs nothing if one taps 5 white creatures; if one only has 5 black creatures, only the 3 colorless mana could be Convoked for a lower cost.
• COUNTERING: Done through instants that specify "counter target spell," along with perhaps other text. When an opponent tries get a card on the field, a counter (Negate, Dissolve, etc.) can be played to prevent its effect from occurring. Counters in this game tend to be blue cards.
• CYCLING: Keyword ability on some cards, each with their own mana cost. If the cost is paid, one discards that card and draws another ("cycling") or can search for a specific card (such as "landcycling"). Which type of cycling is applicable will be said on the card.
• DEATHTOUCH: Keyword ability. Creatures with deathtouch will destroy any creature they deal damage to. Pharika's Chosen (1/1) is chosen to block a Nemesis of Mortals with Monstrosity (10/10). In a normal battle, the two trade blows, and instead of surviving as a 10/9, the beatstick is killed as well. Deathtouch is dealt only any type of damage, but creatures immune to certain types of damage (like Guard Gamazoa) won't be slain. Creatures that pay their regeneration cost aren't destroyed by deathtouch.
• DEFENDER: Keyword ability. Defenders can block but can't attack, which befits their higher toughness. Examples: Wall of Omens, Guard Gomazoa. Some cards (Gargoyle Sentinel, Ogre Jailbreaker) can remove Defender with their own abilities; others will need Warmonger's Chariot to attack. Note that just because they're prevented from attacking, it doesn't mean they don't deal combat damage!
• DESTROY: Type of ability that destroys the target card type, either outright (Flesh to Dust) or when a condition is met (Reprisal, Assassinate). Cards with "indestructible," like Creepy Doll or Darksteel Ingot, are immune to destroy effects. Same goes for cards with protection from the spell's color (ex: the white Divine Verdict does nothing if used on a foe with protection from white).
• DEVOTION: Used in some cards, the value of which is equal to the number of specified mana symbols in mana costs of all permanents one controls. Nylea's Disciple gains life equal to one's devotion to green. Mana symbols in the card text (such as "pay green mana, tap: get X effect") don't count toward devotion.
• DEVOUR: Keyword ability. Creatures with this ability get +1/+1 counters for each creature one sacrifices as it enters the field. How many counters it gets depends on the written text's Devour cost. Thorn-Thrash Viashino has Devour 2, so it gets +2/+2 for each sacrificed creature. Any creature one controls (token, opponent-owned, etc.) can be used for the devour cost.
• DISCARD: Found in many cards means to "send the required amount of cards from hand to graveyard". Mind Rot, for one, would make a target player discard 2 cards. If a player has no cards in their hand, the effect basically does nothing. (Examples: Ostracize, Monomania, Blightening)
• DOMAIN: Keyword ability. This increases a spell's effect based off how many basic land types one owns. For instant, Drag Down gives -1/-1 to a target creature in just this manner. If one controls a Swamp, Mountain and Forest, Drag Down would do more.

Domain: Abilities related to Domain count the number of basic land types you control, topping out at 5.

Double Strike: Creatures with Double Strike deal both first strike and normal combat damage. If a creature with Double Strike fights another creature with Double Strike or First Strike, damage is dealt concurrently.

Enchantment: A type of permanent that stays on the field or is attached to a creature as an Aura. Enchantments remain in play until destroyed. Auras are destroyed when the creature they attach to is destroyed.

Evolve: Creatures with Evolve get a +1/+1 counter each time an ally creature with higher power or toughness enters the field. For instance, a 0/1 Cloudfin Raptor with Evolve would get a +1/+1 counter if a 2/1 Wandering Wolf enters the field, making the Cloudfin Raptor a 1/2. If a 1/1 Young Wolf enters, nothing happens as its power is equal to Cloudfin's.

Exalted: When a creature attacks alone, it gains +1/+1 for every controlled card with Exalted until turn's end. This boost applies to any ally attacker.

Exile: Cards placed in the exile zone are generally removed from the game permanently. Some exiled cards can be brought back through other effects.

Field Nuke: Slang for a card that destroys all or most cards in play. "Nuking the field" means damaging all creatures, often killing most.

First Strike: Cards with First Strike deal damage first when attacking or blocking, instead of concurrently. If two creatures with First Strike attack, concurrent damage is dealt.

Flash: Found on non-instant cards, Flash lets them be played at any time one could play an instant. Some creatures have this ability inherently, while sorceries can gain it through Quicken.

Flashback: Cards with Flashback can be played from the graveyard for a CMC slightly higher than their normal one. This exiles the card.

Flickering: The term for a card that exiles a card and immediately brings it back. This evades targeted spells, removes damage, auras, and equipment. If the card had an effect that triggers when it enters the field, that effect triggers. Flickered targets reappear untapped.

Flying: Creatures with Flying ("flyers") can't be blocked except by creatures with Flying or Reach.

Graveyard: The pile where destroyed creatures, discarded cards, and used instants/sorceries/artifacts end up. Some effects can only be paid while cards are in the graveyard. Some cards exile cards that would end up in the graveyard instead.

Haste: Creatures with Haste can attack as soon as they enter the field, rather than being affected by summoning sickness.

Hellbent: Creatures with Hellbent get an extra effect if their owner has no cards in hand. None of the applicable cards are available to this game's player.

Heroic: Heroic triggers when the applicable creature is targeted by its owner's spell, in addition to whatever that spell does. Heroic can be triggered any number of times per turn but doesn't activate when attaching equipment.

Hexproof: Creatures with Hexproof can't be targeted by the opponent's spells and abilities. They can be sacrificed if they are the only applicable target. The owner of the Hexproof creature can still target it.

Indestructible: Cards with Indestructible aren't destroyed via combat damage or "destroy target creature" effects. They can be returned to hand/deck, placed into the graveyard, or sacrificed.

Instant: A card type. Instant spells can be cast any time, allowing you to respond to an enemy's actions.

Intimidate: (No description provided in source.)