temper
n. C / Un. the way you feel at a certain time, especially if you are feeling angry. If you lose your temper, you stop being calm and start acting in an angry way.
n. a person's state of mind or emotional disposition, particularly regarding the tendency to become angry or irritable. Often used in the context of emotional control or the lack thereof.
He has a very short temper when he is tired.
The manager kept her temper during the difficult meeting despite the constant interruptions from the staff.
While he was generally known for his mild temper, the blatant injustice of the situation provoked a rare and formidable display of indignation.
From Middle English temperen, tempren, from Old English ġetemprian, temprian, borrowed from Latin temperō (“I divide or proportion duly, I moderate, I regulate; intransitive senses I am moderate, I am temperate”), from tempus (“time, fit season”). Compare also French tempérer. Doublet of tamper. See temporal.
Commonly used with the verbs 'lose', 'keep', or 'control'. When referring to a general tendency toward anger, it is countable ('a quick temper'); when referring to a current mood, it is often uncountable.
He lost his tempersHe lost his temperIn the fixed idiom 'lose one's temper', the noun is always singular.