Used setter's revolutionary tactic to get weed regularly (8)
I believe the answer is:
employed
'used' is the definition.
('employ' can be a synonym of 'use')
'setter's revolutionary tactic to get weed regularly' is the wordplay.
'setter' becomes 'me' (the setter of the clue).
'revolutionary' says the letters should be written in reverse.
'tactic' becomes 'ploy' (I have seen 'Clever tactic' mean 'ploy' so perhaps 'tactic' could also mean 'ploy').
'to get' means one lot of letters go next to another.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'weed' are 'ed'.
'me' reversed gives 'em'.
'em'+'ploy'+'ed'='EMPLOYED'
(Other definitions for employed that I've seen before include "in a job" , "Working" , "Gave work to" , "Engaged in paid work" , "Engaged - used" .)