Intense dislike of headgear that's brightly coloured? (6)
I believe the answer is:
hatred
'intense dislike' is the definition.
(I've seen this in another clue)
'headgear that's brightly coloured?' is the wordplay.
'headgear' becomes 'hat' (hats are a type of headgear).
'that's brightly coloured?' becomes 'red' (red is often a bright colour).
'hat'+'red'='HATRED'
'of' acts as a link.
(Other definitions for hatred that I've seen before include "Antipathy" , "Deep dislike and aversion" , "Animus" , "Great dislike" , "hostility" .)