Dreadfully stoned again, getting annoyed (11)
I believe the answer is:
antagonised
'annoyed' is the definition.
(antagonising is a kind of annoying)
'dreadfully stoned again getting' is the wordplay.
'dreadfully' is an anagram indicator.
'getting' says to put letters next to each other.
'stoned'+'again'='stonedagain'
'stonedagain' is an anagram of 'ANTAGONISED'.
(Other definitions for antagonised that I've seen before include "Provoked hostility of" , "Wound up" , "Created hostility in" .)