Seaman? Hardly, yet a safe keeper (9)
I believe the answer is:
custodian
'keeper' is the definition.
(synonyms)
'seaman? hardly yet a safe' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for custodian that I've seen before include "Guardian" , "Protector/guardian (of something)" , "One takes care of" , "museum keeper" , "Protector" .)