Cannabis is too much for her (4)
I believe the answer is:
anna
'her' is the definition.
(I've seen this before)
'cannabis is too much' is the wordplay.
'is too much' says the answer is hidden in the clue (the clue hides the answer plus unneeded letters).
'ANNA' is hidden in the letters of 'cannabis'.
'for' acts as a link.
(Other definitions for anna that I've seen before include "___ Pavlova, Russian dancer, d. 1931" , "Former Indian coin, girl" , "Girl's name (palindrome)" , "Former one sixteenth of Rupee" , "Former Indian coin; girl's name" .)