Instrument played with mallets (7)
I believe the answer is:
marimba
'instrument played with mallets' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for marimba that I've seen before include "Xylophone-like instr." , "Xylophone-like instrument from Africa" , "Latin American instrument like a xylophone" , "Jazz instrument" , "Form of xylophone" .)