The Collaborative International Dictionary
Au fait \Au` fait"\ ([=o]` f[asl]"). [F. Lit., to the deed, act, or point. Fait is fr. L. factum. See Fact.] Expert; skillful; well instructed. [1913 Webster] ||
Douglas Harper's Etymology Dictionary
1743, French, "to the point, to the matter under discussion," literally "to the fact," from fait "fact" (see feat). Used in French with sense of "acquainted with the facts."
Wiktionary
a. Being familiar with or informed about something.
WordNet
adj. being up to particular standard or level especially in being up to date in knowledge; "kept abreast of the latest developments"; "constant revision keeps the book au courant"; "always au fait on the latest events"; "up on the news" [syn: abreast of(p), au courant, up on(p)]
Usage examples of "au fait".
He'd been away so long, she wasn't au fait with the latest developments.
Being a member of the sloppy generation was a boon to my budget at college, where blue jeans were au fait and a dirty sweat shirt was stylish.