Unpleasant refusal to accommodate street (5)
I believe the answer is:
nasty
'unpleasant' is the definition.
(synonyms)
'refusal to accommodate street' is the wordplay.
'refusal' becomes 'nay' (I've seen this before).
'to accommodate' is an insertion indicator.
'street' becomes 'st'.
'nay' enclosing 'st' is 'NASTY'.
(Other definitions for nasty that I've seen before include "Vile" , "Disgusting" , "Beastly" , "Mean" , "Highly repugnant" .)