Get hint about stretch (7)
I believe the answer is:
tighten
'stretch' is the definition.
(thesaurus)
'get hint about' is the wordplay.
'about' indicates anagramming the letters.
'get'+'hint'='gethint'
'gethint' is an anagram of 'TIGHTEN'.
(Other definitions for tighten that I've seen before include "Do this to your belt to economise (7)" , "Apply increased tension or security" , "put the squeeze on" , "Give an extra turn" , "Fasten more firmly" .)