Sailor starts to take another rum (3)
I believe the answer is:
tar
'sailor' is the definition.
(slang term for a sailor)
'starts to take another rum' is the wordplay.
'starts to' suggests taking the first letters.
The first letters of 'take another rum' is 'TAR'.
(Other definitions for tar that I've seen before include "Sailor and dressing for roads" , "Dark viscous stuff" , "one may need to pay on boat" , "Informal sailor or coal distillation" , "Thick, black and sticky liquid" .)