a stalemate or impasse; a confrontation that neither side can win.
Origin
1890-95
Usage note
This expression is sometimes perceived as insulting to or by Mexicans. Its origin in the late 19th century may be connected to American perceptions of encounters with Mexican bandits of that era.
Slang definitions & phrases for Mexican standoff
Mexican standoff
noun phrase
A stalemate; deadlock; standoff •First referred to a tie baseball game (1891+)