Mad Hatter's guest (5)
I believe the answer is:
alice
'mad hatter's guest' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for alice that I've seen before include "She ate the "Eat Me" and drank the "Drink Me"" , "Wonderland girl's name" , "Carroll heroine" , "... Walker, ... Munroe (writers)" , "Movement" .)