Whom dad will regard as a sailor (6)
I believe the answer is:
popeye
'sailor' is the definition.
(I have seen 'comic sailor' mean 'popeye' so perhaps 'sailor' could also mean 'popeye')
'whom dad will regard as a' is the wordplay.
I cannot quite see how this works, but
'dad' could be 'pop' (synonyms) and 'pop' is found in the answer.
'regard' could be 'eye' (I've seen this before) and 'eye' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for popeye that I've seen before include "Cartoon spinach eater" , "mariner?" , "Spinach-eating cartoon character" , "Bluto's rival" , "Spinach and Olive Oyl lover" .)