WordNet sense 1 (a characteristic (habitual or relatively temporary) state of feeling):

humor, mood, humour

WordNet sense 2 (a sudden outburst of anger):

irritation, pique, pique

WordNet sense 3 (the elasticity and hardness of a metal object; its ability to absorb considerable energy before cracking):

toughness

WordNet sense 4 (a disposition to exhibit uncontrolled anger):

biliousness, irritability, peevishness, surliness, pettishness, snappishness

WordNet sense 5 (toughen (steel or glass) by a process of gradually heating and cooling):

anneal, normalize

WordNet sense 6 (harden by reheating and cooling in oil):

harden

WordNet sense 7 (make more temperate, acceptable, or suitable by adding something else; moderate):

mollify, season

WordNet sense 8 (restrain or temper):

chasten, moderate, moderate