Dilates, gaining nothing somehow, and is deserted (8)
I believe the answer is:
isolated
'is deserted' is the definition.
(thesaurus)
'dilates gaining nothing somehow' is the wordplay.
'gaining' is a charade indicator (letters next to each other).
'nothing' becomes 'O' (looks like zero - 0).
'somehow' is an anagram indicator.
'dilates'+'o'='dilateso'
'dilateso' anagrammed gives 'ISOLATED'.
'and' is the link.
(Other definitions for isolated that I've seen before include "Placed alone" , "Single" , "Separated from others" , "Remote, set apart" , "Idols ate (anag.)" .)