Sanctimonious seaman stealing (8)

I believe the answer is:

pirating

'stealing' is the definition.
(pirating is a kind of stealing)

'sanctimonious seaman' is the wordplay.
'sanctimonious' becomes 'pi' (British abbreviation for pious).
'seaman' becomes 'rating' (British term for a naval enlisted man).
'pi'+'rating'='PIRATING'

(Other definitions for pirating that I've seen before include "running off illicitly" , "bootlegging" .)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app