noun
concealed hand with tiles of only one suit (mahjong)
In mahjong, a hand where all tiles are of a single suit and the player has not called any tiles (i.e., the hand is fully concealed). Sometimes also used for a hand that is one-suit and concealed regardless of calls. Compare メンゼン (concealed hand) and 清一色 (full flush).
from Chinese
メンチンで上がれば高得点が狙える。
If you win with a concealed single-suit hand, you can aim for a high score.
彼はメンチンをテンパイしている。
He is one tile away from a concealed single-suit hand.