Objection chapter is tough (5)
I believe the answer is:
butch
'tough' is the definition.
(I've seen this before)
'objection chapter' is the wordplay.
'objection' becomes 'but' (as in 'no ifs, no buts').
'chapter' becomes 'ch'.
'but'+'ch'='BUTCH'
'is' is the link.
(Other definitions for butch that I've seen before include "Markedly masculine" , "Aggressively masculine" , "Macho" , "Acting as a male (colloq.)" , "Tough" .)