Resent worker consuming fantastic drug by gram (8)
I believe the answer is:
begrudge
'resent' is the definition.
('begrudge' can be a synonym of 'resent')
'worker consuming fantastic drug by gram' is the wordplay.
'worker' becomes 'bee' (I've seen this before**).
'consuming' means one lot of letters goes inside another.
'fantastic' indicates anagramming the letters.
'by' is a charade indicator (letters next to each other).
'gram' becomes 'g' ('g' can be a synonym of 'gram').
'drug'+'g'='drugg'
'drugg' anagrammed gives 'grudg'.
'bee' enclosing 'grudg' is 'BEGRUDGE'.
(Other definitions for begrudge that I've seen before include "Resent other's good fortune or possession" , "Envy another's possessions or good fortune" , "Envy, have feeling of resentment" , "Envy (someone) the possession of" , "Envy the pleasure of" .)