Sailor starts saying .. "The ploy is puzzling" .... (8)
I believe the answer is:
abstruse
'is puzzling' is the definition.
(thesaurus)
'sailor starts saying the ploy' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'starts' indicates taking the first letters.
'ploy' becomes 'ruse' (I've seen this before).
The initial letters of 'saying the' is 'st'.
'ab'+'st'+'ruse'='ABSTRUSE'
(Other definitions for abstruse that I've seen before include "Strange busts are difficult to understand" , "Busts are oddly difficult to understand" , "Esoteric" , "Hard to understand, perhaps profound" , "Incomprehensible to those with normal understanding" .)