IPA: //ˈhɒtˌhɛd.ɪd.nəs//
KK: /hɑtˈhɛdɪdnəs/
The quality of being easily angered or quick to react with anger.
His hotheadedness often led to arguments with his friends.
Hotheadedness → It is formed from "hot" (from Old English *hat*, meaning having a high temperature or being heated) and "headed" (from Old English *heafod*, meaning the top or leader) combined with the suffix "-ness" (meaning the state or quality of). The word describes the state of being easily angered or having a fiery temperament.
Think of someone who is 'heated' ('hot') and has a 'leading' ('headed') temperament, which helps you remember that 'hotheadedness' refers to the quality of being easily angered.