Amuse many with rowing team circling lake (7)
I believe the answer is:
delight
'amuse' is the definition.
(thesaurus)
'many with rowing team circling lake' is the wordplay.
'many' becomes 'd'.
'with' says to put letters next to each other.
'rowing team' becomes 'eight' (I've seen this before).
'circling' indicates putting letters inside (circling can mean going around or containing).
'lake' becomes 'L' (geographical abbreviation).
'eight' placed around 'l' is 'elight'.
'd'+'elight'='DELIGHT'
(Other definitions for delight that I've seen before include "''A lonely impulse of ...'' (Yeats)" , "Enjoyment" , "Give great pleasure to" , "Joy" , "Elation" .)