Sailor overwhelmed by abominable sound (6)
I believe the answer is:
viable
'sound' is the definition.
(I've seen this before)
'sailor overwhelmed by abominable' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'overwhelmed by' means one lot of letters goes inside another (inserted letters get absorbed or overwhelmed).
'abominable' becomes 'vile' (synonyms).
'ab' placed into 'vile' is 'VIABLE'.
(Other definitions for viable that I've seen before include "Able to survive; practicable" , "having potential to succeed" , "Having a prospect of success" , "reasonable hope of success" , "Capable of independent life" .)