A fighter ability, more often referred to as a passive ability, character mechanic, or character gimmick is an unofficial term used in fighting games, including the Super Smash Bros. series, that describes special mechanics specific to certain characters (and/or their clones). They can grant said fighter a passive ability, a chargeable meter, extra moves in their arsenal, an ammunition system, or other mechanics that are not directly linked to their standard moveset. In Super Smash Bros. Ultimate, many fighter abilities have a special icon on the character's damage meter and/or a separate section in the character's Move List.
Certain moves and mechanics can be described as a character's "gimmick", but aren't strictly fighter abilities due to being too universal or restricted to a single move. Specifically, this applies to the following:
List of fighter abilities
Game icons indicate that the mechanic was only used in those specific games.
Single fighters and clones
In addition to the above, certain mechanics and abilities are present on multiple non-clone fighters, but are not universal throughout the roster.