Intense dislike of headwear colour (6)
I believe the answer is:
hatred
'intense dislike' is the definition.
(I've seen this before)
'headwear colour' is the wordplay.
'headwear' becomes 'hat' (hat is a type of headwear).
'colour' becomes 'red' (red is a kind of colour).
'hat'+'red'='HATRED'
'of' is the link.
(Other definitions for hatred that I've seen before include "Detestation, loathing" , "Antipathy" , "Animus" , "Extreme dislike and enmity" , "hostility" .)