Inspection working with guard to seize drug (4-4)
I believe the answer is:
once-over
'inspection' is the definition.
(I've seen this before)
'working with guard to seize drug' is the wordplay.
'working' becomes 'on' (e.g. a machine is working or on).
'with' says to put letters next to each other.
'guard' becomes 'cover' ().
'to seize' means one lot of letters goes inside another.
'drug' becomes 'e' (E is another name for ecstasy).
'cover' enclosing 'e' is 'ceover'.
'on'+'ceover'='ONCE-OVER'
(Other definitions for once-over that I've seen before include "Quick inspection" , "Cursory examination" , "Quick survey" , "Brief check" , "Appraising glance" .)