Большой русско-английский фразеологический словарь

Я16

ОСТЁР (ОСТРЫЙ) НА ЯЗЫКcollAdjPsubj-complwith copula,subj:human(all variants) ormodif(var.with long-formAdj)fixedWO

a person who is sarcastic and biting in conversation
X остёр на язык - X has a sharp tongue
X is sharp-tongued.