What is one word that can be used to describe someone who likes to party and go to clubs?
In addition to Edwin Ashworth's excellent suggestions of socialite and party animal I can make a few suggestions.
All of these uses are slang/idiomatic hence they might be readily available in a thesaurus or standard reference.
Partier (alternatively partyer) - usually a negative connotation.
(Note - the proper usage of this term is to describe a party attendee. This usage is slangy.)
Clubber - similar to partier.
(Note - the proper usage of this term is to describe someone wielding a club, typically to beat something like a baby seal to death.)
Also, an old-fashioned term: Good Time Charlie
I think this usage is quite antiquated, but it remains useful.