already (adv.) Look up already at Dictionary.com
c.1300, compound of all + ready (adj.); literally "fully ready." Compare Norwegian, Danish allerede "already." Colloquial use in U.S. as a terminal emphatic (as in enough, already!) is attested from 1903, translating Yiddish shoyn, which is used in same sense. The pattern also is attested in Pennsylvania German and in South African.