(no subject)
大功告成
dà gōng gào chéng
大 [Adj.]big, large, great, eldest, important, major, serious. Here it only means big. ^_^
功 [Noun]work, achievement, heroic achievement, skill, project. (Almost the same thing except "skill".)
告 [Verb]report, tell, accuse, ask for, declare. [Noun]statement. Here it should mean declare or state.
成 [Verb]accomplish, succeed, become, form. [Noun]success. [Adj.]standing, entire(There's a localism word 成天, but it doesn't mean a whole day, it means every day).
告成 (Something) be accomplished.
My rough translation:
A big project is declared accomplished.
大功告成 means accomplishment of a project (task, work), or be crowned with success. (Mission accomplished!)
Usage:
Chinese: 这件事可就算是大功告成了。
Attention:
This idiom is usually used as an adjective. But if you want to use it, make sure it's a big deal or some hard work being "accomplished". This is the main difference between 大功告成 and 告成. Don't use it on fetching toilet-paper or something!