Strong narcotic figure's inhaled (6)
I believe the answer is:
potent
'strong' is the definition.
(similar in meaning)
'narcotic figure's inhaled' is the wordplay.
'narcotic' becomes 'pot' (pot is a kind of narcotic).
'figure' becomes 'ten' (ten is a number or figure).
'inhaled' indicates putting letters inside.
'pot' enclosing 'ten' is 'POTENT'.
(Other definitions for potent that I've seen before include "Forceful" , "Concentrated or strong, like liquor" , "Strong in operation" , "Maybe overpowering" , "Mighty" .)