give it a whack
i know that whack means hit, literally i give it a whack may mean the show is a success.(fyi, it's said by a boy after a show )while under the context,it's better if it's translated into "i blowed the show" .so what does "give it a whack" exactly mean?

Question

give it a whack 
i know that whack means hit, literally i give it a whack may mean the show is a success.(fyi, it's said by a boy after a show )while under the context,it's better if it's translated into "i blowed the  show"  .so what does "give it a whack" exactly mean?

Answer

"Give it a whack" has two possible meanings:

1. Hit it.

2. Give it a try.  You hear this more as "Take a whack at it.", but this phrase is used.  I am just not quite sure how it fits into the context.

Answer

give it a which = give it a go = give it a try

It does not imply success or failure. It simple says: "Give it a try."

Answer

I'm a native speaker and I have never heard this phrase. Where exactly did you hear it? Also, in your case the meaning would be figurative (which implies an idiomatic meaning), as opposed to literal (which implies a non-idiomatic meaning).

Also, the alternate translation (*I blew the show) is just slang for "The show went badly" or "I ruined the show".