To Negate a card is to prevent a card from activating, using its effect and/or being Summoned. Destroying a card is not the same as negating the card. E.g. When a player activates "Dark Hole" and the other player activates "Mystical Space Typhoon", it will only send the activated card, Dark Hole, to the Graveyard, but its effect will remain on the field, so the monsters are still destroyed.
Such card examples that negate are:
- Using "Seven Tools of the Bandit" on "Royal Decree"
- Using "Magic Jammer" on "Monster Reborn"
- Using "Trap Jammer" on "Mirror Force"
- Using "Skill Drain" on "Chaos Sorcerer"
- Using "Solemn Judgment", "Horn of Heaven" or "Forced Back" on the Summoning of "Jinzo"
To negate an attack is to stop a battle from taking place and preventing the monster from attacking again during the same turn. Examples include "Magic Cylinder", "Draining Shield", or "Negate Attack".