To pirate (10)
I believe the answer is:
plagiarise
'to pirate' is the definition.
('pirate'->'plagiarize' is in my internal thesaurus and 'ize'->'ise')
This is all the clue.
(Other definitions for plagiarise that I've seen before include "Cheat by copying; agile pairs (anag.)" , "appropriate" , "lift!" .)