Able to go topless in bar (5)
I believe the answer is:
lever
'bar' is the definition.
(I know that lever is a type of bar)
'able to go topless' is the wordplay.
'able' becomes 'clever' (I've seen this before).
'to go topless' means to remove the first letter.
'clever' with its first letter removed is 'LEVER'.
'in' is the link.
(Other definitions for lever that I've seen before include "Purchase from bar" , "Jemmy" , "Lifting device to revel in" , "Machine operator" , "Exert pressure" .)