Antipathy that is largely contrived (7)
I believe the answer is:
allergy
'antipathy' is the definition.
(I've seen this in another clue)
'largely contrived' is the wordplay.
'contrived' indicates an anagram.
'largely' with letters rearranged gives 'ALLERGY'.
'that is' acts as a link.
(Other definitions for allergy that I've seen before include "unhealthy reaction" , "Producer of Hay Fever" , "Immune reaction" , "Abnormal body reaction" , "Abnormal sensitivity to a food" .)