Bullied by party wits consuming lots of drugs and a fair amount of grass (10)
I believe the answer is:
domineered
'bullied' is the definition.
(domineering is a kind of bullying)
'party wits consuming lots of drugs and a fair amount of grass' is the wordplay.
I cannot quite understand how this works, but
'party' could be 'do' (do is a kind of party) and 'do' is found in the answer.
'lots' could be 'm' and 'm' is located in the answer.
'drugs' could be 'ee' (an abbreviation for ecstasy written twice) and 'ee' is located in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
'amount' could be 'r' (R is an example) and 'r' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'by' is the link.
Can you help me to learn more?
(Another definition for domineered that I've seen is " Acted arrogantly".)