In Reply to: Crack on posted by Victoria S Dennis on June 19, 2008 at 16:27:
: : I knew a man who used the phrase 'crack on' as a synonym for 'you must be kidding', or 'get real'. Has anybody else come across this, and do you think it might be related to the Irish 'craic'?
: I haven't come across this, but your suggested derivation sounds unlikely to me. "Crack on" means "to progress briskly" (cf. "get cracking"), and as such its usage to mean "you must be kidding" is precisely analogous to a whole raft of phrases like "Get along with you!" "Get away!" "Garn(i.e. "Go on")!(VSD)
"Crack on" in Australia means to "woo a member of the opposite sex" as Kevin Bloody Wilson's (an Australian Comedian) web page puts it coyly. http://www.kevinbloodywilson.com/site/aussie-slang/
More straightforwardly it means to try to have sex with someone e.g. "he was trying to crack on to her". Pamela