Bluegrass strings (5)
I believe the answer is:
banjo
'bluegrass strings' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for banjo that I've seen before include "Small plucked instrument" , "Relative of the guitar" , "Long-necked instrument" , "Stringed instrument of the guitar family" , "Five-stringed musical instrument" .)