Loathing test, said to be complicated (8)
I believe the answer is:
distaste
'loathing' is the definition.
(I've seen this before)
'test said to be complicated' is the wordplay.
'to be complicated' is an anagram indicator.
'test'+'said'='testsaid'
'testsaid' anagrammed gives 'DISTASTE'.
(Other definitions for distaste that I've seen before include "Negative feeling" , "Dislike of something unsavoury" , "Mild dislike, aversion" , "Staidest (anag) - aversion (to)" , "lack of relish?" .)