(idiomatic) Used to tell someone to control their (bad) temper

Capable of being tempered.

To moderate or control. / To strengthen or toughen a material, especially metal, by heat treatment; anneal.

A general tendency or orientation towards a certain type of mood, a volatile state; a habitual way of thinking, behaving or reacting. / State of mind; mood. / A tendency to become angry.

The ability to be tempered.

Misspelling of temperament.

plural of temperment

A person who tempers (in any meaning). / A device that tempers; an annealer. / A machine in which lime, cement, stone, etc., are mixed with water.

(medicine, archaic) A drug that allays a fever.

temperate, moderate / sober