(idiomatic,Brazil) for something catastrophic to occur; used in the format “pode chover canivete mas ...” (It could rain pocketknives but ...), “... nem que chova canivete” (... even if pocketknives rain), or similar, to indicate that something else will occur no matter what
Não saio daqui nem que chova canivetes.
I won’t leave this place no matter what.
(idiomatic,Brazil)used to indicate that something very unlikely happened