In a 1951 Humphrey Bogart film (The Enforcer; Murder Inc in the UK), both the DA and the police are befuddled by the terms 'hit' (noun form, meaning 'a person designated to be killed') and 'contract' (as in 'put out a contract on'). Indeed, much is made in the early part of the film about their not understanding what these word refer to. And my Random House Unabridged gives the date of origin for 'hit man' as 1965-70. Are all these terms really that recent?

Welcome aboard, Eddie! That is one heck of an excellent question.

Who was our resident expert [Sparteye?] on slang? Could this trace back to slang from the criminal class?

Welcome! I've got no special insight available Eddie, but I guess I had always assumed the noun form was, ahem, a contraction from the description of a contract killer, thus to 'taking out a contract', thus to just 'contract'. But who knows - maybe the journey was the other way - I shall watch with interest.

The use of the verb to hit seems plainer, being a natural extension of other violent movement associated with the word - especially when you think of the French cognate abattre, leading to our word abattoir.

How interesting, Eddie. I, too, am surprised that these terms are so recent. I guess I'd subconsciously planted them firmly in the gangster days of the 1920s.

My slang and etymological dictionaries offer no help, perhaps because the meanings are still fairly close to the original meanings of the terms.

To "hit" includes to strike, which is the point of and the method of execution (*heh*) of a hit.

I agree with Maverick that a "contract" probably is a contraction of "contract killer" - a killer who is under contract, hired to do the deed for an agreed price.