It does not necessarily mean "why". There might be some difference depending on the context. "He does what for him?" would be asking what he does for him. It also might register suprise or disbelief. "I walk his dogs in the morning." "You do WHAT for him?" (This person can't believe that the speaker would walk the dogs). "What for" is also an idiom - "When he came home late, his wife gave him what for." might mean that she gave him a very difficult time As for "for what" it might still mean what. "He's doing all this for what? Just to get into the club?" This would be expressed as "What is he getting out of his efforts?"

Your question [This is better English]:- I heard those expressions on TV and I don`t know the difference between THEM. DO THEY Mean the same THING? ARE They used IN different situations? My answer:- "I have a gun" "What for?" [This means - "Why do you need to have a gun, is there a reason for having it?"] "I have a gun" "For what?" [This means - "What are you going to do with the gun, how are you going to use it?"] Suggestion: The next time you hear something on TV try to remember the whole sentence. It is easier for to explain in context. Good luck Stephen

More examples: Irritable parent: 'Stop that noise!' Child: 'What for? I'm not hurting anyone' Child: 'Guess what? I traded my ipod for a bag of lollies today' Upset mother exclaims: 'For what?'

They mean the same thing. They both mean "why".

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