Someone who is quick-tempered.
From the Greek oxy meaning sharp, acute and thymos meaning emotions, breath, soul.
“Knowing his girlfriend was notoriously oxythymous Brad refrained from telling Jen he had forgotten to book the restaurant ahead of time. When they arrived and were refused a table Brad was content to let the doorman get yelled at in his place. They got burgers instead.”
Love Tahlia, updating early because she uses her class time efficiently, cough cough.