To refrain from becoming angered, enraged, or upset due to some provocation; to maintain control of one's composure despite being angry or upset. You're a good driver, but you need to do a better job of keeping your temper when other drivers make mistakes. It's hard to keep my temper with the kids after being kept awake by them all night long.

To become angered, enraged, or upset due to some provocation; to have an outburst upon losing one's patience. I'm usually a pretty calm person, but whenever I start driving, I find I lose my temper at the slightest inconvenience. When we were kids, my dad lost his temper a lot, but he's mellowed out since then.