Lots of workmen make jokes, out for a bit of fun (5)
I believe the answer is:
gangs
'for a bit of fun' is the definition.
I can't judge whether this defines the answer.
'lots of workmen make jokes out' is the wordplay.
'lots of workmen make' becomes 'n' (I can't justify this - if you can you should believe this answer much more).
'jokes' becomes 'gags' (gag can mean a joke).
'out' indicates putting letters inside.
'n' inserted inside 'gags' is 'GANGS'.
Can you help me to learn more?
(Other definitions for gangs that I've seen before include "bands" , "Criminal groups" , "Mobs" .)