Expand in elaborate detail (6)
I believe the answer is:
dilate
'expand' is the definition.
(thesaurus)
'elaborate detail' is the wordplay.
'elaborate' indicates an anagram (I've seen this in other clues).
'detail' is an anagram of 'DILATE'.
'in' acts as a link.
(Other definitions for dilate that I've seen before include "Tailed (anag)" , "explain more fully" , "Widen, distend" , "contract? No" , "Widen like eye pupils" .)