Fed up like Ted about the tax people (5)
I believe the answer is:
tired
'fed up' is the definition.
(thesaurus)
'ted about the tax people' is the wordplay.
'about' is an insertion indicator.
'the tax people' becomes 'ir'.
'ted' enclosing 'ir' is 'TIRED'.
'like' acts as a link.
(Other definitions for tired that I've seen before include "Ready to drop" , "In need of rest" , "Beat" , "Drowsy" , "ready for bed" .)