Rugged old seaman (5)
I believe the answer is:
hardy
'rugged' is the definition.
(similar in meaning)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for hardy that I've seen before include "Rugged; author" , "able to bear exposure" , "Author Thomas?" , "flag-captain" , "16 novelist" .)