Indian instrument is taken up by sailor (5)
I believe the answer is:
sitar
'indian instrument' is the definition.
(I've seen this in another clue)
'is taken up by sailor' is the wordplay.
'taken up' says the letters should be written in reverse.
'by' is a charade indicator (letters next to each other).
'sailor' becomes 'tar' (tar can mean a sailor).
'is' back-to-front is 'si'.
'si'+'tar'='SITAR'
(Other definitions for sitar that I've seen before include "music producer" , "Guitar-like instrument" , "Lasting from morning to night" , "Astir with Indian long-necked lute" , "Stringed instrument of the subcontinent" .)