noun; Grand four happiness in mahjong game, to win the game
Definitions (粵典–words.hk)
名詞、術語
麻雀術語；麻雀牌型一種，要用東、南、西、北各碰一次，另加任意一對眼；又稱四喜臨門 Mahjong jargon; Great Wind Hand - a formation of 4 triplets(pongs) on all Wind tiles (East, South, West, North), and add a pair of eyes of any suit.
Definitions (Wiktionary)
noun
a winning hand with melds of all four wind tiles