v. To strike with a heavy, crushing blow: The thug bashed the hood of the car with a sledgehammer. v. To beat or assault severely: The police arrested the men who bashed an immigrant in the park. v. Informal To criticize (another) harshly, accusatorially, and threateningly: "He bashed the . . . government unmercifully over the . . . spy affair” ( Lally Weymouth). verb-intransitive. Informal To engage in harsh, accusatory, threatening criticism.n. Informal A heavy, crushing blow.n. Slang A celebration; a party.