Pungent air around middle of restroom (6)
I believe the answer is:
strong
'pungent' is the definition.
(thesaurus)
'air around middle of restroom' is the wordplay.
'air' becomes 'song' (I've seen this before**).
'around' means one lot of letters goes inside another.
'middle of' indicates the central letters.
The central letters of 'restroom' are 'tr'.
'song' placed around 'tr' is 'STRONG'.
(Other definitions for strong that I've seen before include "firm" , "Physically powerful - feel 1 Across" , "Powerful; highly alcoholic" , "curator" , "Not easily broken" .)