noun

a violent confrontation.

there have been minor clashes with security forces

confrontation,skirmish,brush,encounter,engagement,collision,incident,conflict,fight,battle,hostilities,fighting,warring,rencounter

verb

meet and come into violent conflict.

soccer hooligans clashed with rival fans before the match

fight,skirmish,contend,come to blows,be in conflict,come into conflict,engage,war,grapple,do battle,confront,attack