French Canadian sacre (swear) which can be roughly translated as fuck or damn. It comes from the retaille d'osti which is a kind of religious bread.
«Mon osti de chien sale de tabarnak de caliss de criss !»
«Big Dave c'est po une osti de rafiole, mais toé t'est le roi des fifs»
«Think big, 'sti» - Bob Gratton
