Objection's raised showing butt (4)
I believe the answer is:
stub
'butt' is the definition.
(I know that butt can be written as stub)
'objection's raised' is the wordplay.
'objection's' becomes 'but's' (as in 'no ifs, no buts').
'raised' shows that the letters should be reversed in order (going up in a down clue).
'buts' written backwards gives 'STUB'.
'showing' is the link.
(Other definitions for stub that I've seen before include "Short bit of pencil, say" , "Put out" , "Short remaining piece" , "Remnant, butt" , "Truncated remnant" .)