Annoy, wearing a tie after getting trendy hair (9)
I believe the answer is:
infuriate
'annoy' is the definition.
(thesaurus)
'wearing a tie after getting trendy hair' is the wordplay.
'wearing' indicates anagramming the letters (wear can mean to become damaged).
'after getting' means one lot of letters go next to another.
'trendy' becomes 'in' ('in' can mean fashionable).
'hair' becomes 'fur' (fur is a kind of hair).
'a'+'tie'='atie'
'atie' anagrammed gives 'iate'.
'in'+'fur'='infur'
'iate' put after 'infur' is 'INFURIATE'.
(Other definitions for infuriate that I've seen before include "anger" , "Enrage or exasperate" , "Make someone very angry" , "get very warm" , "incense" .)