Seaman I confused shows memory loss (7)
I believe the answer is:
amnesia
'memory loss' is the definition.
(synonyms)
'seaman i confused' is the wordplay.
'confused' indicates an anagram.
'seaman'+'i'='seamani'
'seamani' with letters rearranged gives 'AMNESIA'.
'shows' is the link.
(Other definitions for amnesia that I've seen before include "Am I sane? (anag)" , "Memory-loss" , "Asia men with memory loss (7)" , "Failure to recall" , "Is a name (anag.)" .)