Talk of a grand seaman (3)
I believe the answer is:
gab
'talk' is the definition.
(thesaurus)
'a grand seaman' is the wordplay.
'a grand' becomes 'g' (synonyms).
'seaman' becomes 'ab'.
'g'+'ab'='GAB'
'of' is the link.
(Other definitions for gab that I've seen before include "Loquacity the gift of it" , "Talk at length, chatter" , "Talk a lot" , "gossip" , "The gift of the . . . is ability to talk fluently" .)