Nonsense from sailor, a cheat (10)
I believe the answer is:
taradiddle
'nonsense' is the definition.
(taradiddle is a kind of nonsense)
'sailor a cheat' is the wordplay.
'sailor' becomes 'tar' (tar is a kind of sailor).
'cheat' becomes 'diddle' (diddling is a kind of cheating**).
'tar'+'a'+'diddle'='TARADIDDLE'
'from' acts as a link.
(Other definitions for taradiddle that I've seen before include "Fiddlesticks!" , "Nonsense" , "Tripe" .)