choler, enmity, temper, rankle
Exasperation.
One three letter word relating to anger and ending with O is ego.
anger
Anger
The definition of the word 'annoyance' is the feeling of being irritated. Some synonyms for this word would be anger, irritation, unhappiness, and frustration.
ire
enraged
scorn, anger
rage
Vent could mean release anger.
stressed i think
enraged