Perplex loud clumsy person (7)
I believe the answer is:
flummox
'perplex' is the definition.
('flummox' can be a synonym of 'perplex')
'loud clumsy person' is the wordplay.
'loud' becomes 'f' (A musical term).
'clumsy person' becomes 'lummox' (lummox is a kind of clumsy person).
'f'+'lummox'='FLUMMOX'
(Other definitions for flummox that I've seen before include "Perplex" , "'Confuse, bewilder (7)'" , "Puzzle" , "Confound" , "Bewilder, beat" .)