Unexcited by some musical medley (4)
I believe the answer is:
calm
'unexcited' is the definition.
(similar in meaning)
'some musical medley' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'CALM' can be found hidden inside 'musical medley'.
'by' is the link.
(Other definitions for calm that I've seen before include "Pacific" , "Cool and collected" , "Peaceful, not excited" , "Still and quiet" , "Placid and unruffled" .)