Short for 安全牌 (anzenpai).

(mahjong) a tile that one can safely discard, as it cannot become an opponent's advantage / (slang, by extension) a safe choice

A signboard; a doorplate

(mahjong) short hand (illegal hand containing too few tiles)

(mahjong) being one tile away from completing a hand

(mahjong) to be one tile away from completing a hand

(mahjong) flower tile (included in mahjong sets, but not used in Japanese mahjong gameplay)

(mahjong) long hand (illegal hand containing too many tiles)

(mahjong) red tile; unique to Japanese mahjong and used to score bonus points

having a comeback or excuse for everything one is told, being smart in the sense of having a smart mouth