Wonderland visitor takes head off ill-will (5)
I believe the answer is:
alice
'wonderland visitor' is the definition.
(I've seen this before)
'head off ill-will' is the wordplay.
'head off' means to remove the first letter.
'ill-will' becomes 'malice' (I've seen this before).
'malice' with its first letter removed is 'ALICE'.
'takes' is the link.
(Other definitions for alice that I've seen before include "Wonderland visitor" , "Celia changes into a different girl" , "She ate the "Eat Me" and drank the "Drink Me"" , "Wonderland girl; --- B. Toklas" , "Movement" .)