One dislikes headgear carried by old queen (5)
I believe the answer is:
hater
'one dislikes' is the definition.
(I know that hater detest)
'headgear carried by old queen' is the wordplay.
'headgear' becomes 'hat' (hats are a type of headgear).
'carried by' says to put letters next to each other (in a down clue, some letters hold up others).
'old queen' becomes 'ER' (Elizabeth Regina, ie Queen Elizabeth).
'hat'+'er'='HATER'
(Other definitions for hater that I've seen before include "Heart (anag.)" , "He loathes" , "Person showing animosity" , "I really can't stand" , "One who shows intense dislike" .)