a characteristic cast of mind or state of feeling

Scrooge resumed his labours with an improved opinion of himself, and in a more facetious temper than usual with him — Dickens

characteristic tone

You could put that down to the temper of the times

the state of a substance with respect to certain desired qualities, e.g. the degree of hardness or resilience given to steel by tempering

(+ with) to moderate (something harsh) with the addition of something less severe

We must temper justice with mercy

to bring (something) to a suitable state, esp by mixing in or adding a liquid ingredient, esp to mix (clay) with water or a modifier and knead to a uniform texture

to bring (esp steel) to the right degree of hardness by reheating and cooling it

to strengthen the character of (somebody) through hardship

All his troops had been tempered in battle

to adjust the pitch of (a note, chord, or instrument) to a temperament