Refers to one's social standing, dignity, or reputation, especially in the context of not losing face. Common in phrases like メンツを保つ (to save face) or メンツが立たない (to lose face).
from Chinese miànzi
彼は部下の前でメンツを保とうとした。
He tried to save face in front of his subordinates.
If you do that, his reputation will be completely ruined.
In mahjong, a set of tiles declared as a combination (e.g., a pung or chow).
He quickly called a meld and advanced his hand.
The group of players participating in a mahjong game; often used when talking about gathering enough people to play.
Tonight's lineup is the usual three plus one newcomer.
attendees; members; participants
Colloquial extension from mahjong; refers to the people present at a meeting, event, or gathering. Often used in casual conversation.
Today's drinking party lineup is pretty impressive, isn't it?
I argued back in front of the boss and made him lose face.
We don't have enough players today, so we can't play mahjong.
He's always so worried about saving face that he can't apologize honestly.