Disagreeable moose in for treatment (7)
I believe the answer is:
noisome
'disagreeable' is the definition.
(I've seen this before)
'moose in for treatment' is the wordplay.
'for treatment' indicates an anagram (I've seen this in other clues).
'moose'+'in'='moosein'
'moosein' anagrammed gives 'NOISOME'.
(Other definitions for noisome that I've seen before include "Repellent" , "Offensively malodorous" , "noxious smells" , "Rank" , "Having an extremely offensive smell" .)