Recruit found floating structure in river (7)
I believe the answer is:
draftee
'recruit' is the definition.
(thesaurus)
'floating structure in river' is the wordplay.
'floating structure' becomes 'raft' (I've seen this before).
'in' indicates putting letters inside.
'river' becomes 'dee' (River Dee).
'raft' going inside 'dee' is 'DRAFTEE'.
'found' is the link.
(Other definitions for draftee that I've seen before include "One forced to join" , "one brought into service" , "Rookie" , "American military conscript" , "Soldier, perhaps unwilling" .)