Loud note played outside many times (5)
I believe the answer is:
often
'many times' is the definition.
(synonyms)
'loud note played outside' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'played' is an anagram indicator (letters playing around).
'outside' is an insertion indicator (some letters go outside others).
'note' is an anagram of 'oten'.
'f' going inside 'oten' is 'OFTEN'.
(Other definitions for often that I've seen before include "Perhaps daily" , "In many instances" , "Frequent" , "Much of the time" , "Repeatedly with regularity" .)