Modern section of leisure centre (6)
I believe the answer is:
recent
'modern' is the definition.
(thesaurus)
'section of leisure centre' is the wordplay.
'section of' indicates the answer is hidden within the clue.
'RECENT' can be found hidden inside 'leisure centre'.
(Other definitions for recent that I've seen before include "Fresh, modern" , "Not long ago, a little while back" , "Having happened lately" , "Done not long ago" , "Present day" .)