anyone; anybody; everyone; whoever
Emphatic or colloquial expression meaning 'anyone at all' or 'everyone without exception'. Similar to 誰でも but with a slightly more informal, conversational tone.
See also: 誰でも (だれでも)
誰だって失敗することはある。
Anyone can make mistakes.
そんなことは誰だって知っているよ。
Everybody knows that.
Combination of 誰 (who) and だって (even, also), a colloquial particle derived from だ + とて. The expression literally means 'even who' and extends to 'anyone' or 'everyone'.