attemper
To temper by adjusting relative quantities, or blending qualities.
To mitigate, assuage.
But we must add, that she did say, by way of attempering her pleasure: "Well! I must say I never saw a finer young man in my life—indeed I don’t know that the court of Great Britain quite boasts his equal...
To regulate, arrange, organise.
archaic
Thus fairely she attempered her feast, / And pleasd them all with meete satietie [...].
Where it comes from
From Middle English attempren, from Old French atemprer (French attremper), from Latin attemperare. Doublet of attemperate.
Adapted from the Wiktionary entry attemper (CC BY-SA 4.0).