Beetle could be sailor's car (6)
I believe the answer is:
scarab
'beetle' is the definition.
(scarab is a kind of beetle)
'sailor's car' is the wordplay.
I cannot really understand how this works, but
'sailor' could be 'ab' (abbreviation for able seaman) and 'ab' is found in the answer.
The remaining letters 'scar' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'could be' acts as a link.
Can you help me to learn more?
(Other definitions for scarab that I've seen before include "Dung beetle - ancient Egyptian cut gem" , "crawler" , "Sacred Eygptian beetle" , "insect" , "Beetle, sacred to the ancient Egyptians" .)