> temper (1) to soften; mollify (2) to strengthen (e.g. a metal)
Not contradictory because hardness and toughness are 2 distinct (though correlated) properties. Tempering [1] is basically a process that trades some hardness (i.e. soften) for a lot of toughness (i.e. strengthen).
Not contradictory because hardness and toughness are 2 distinct (though correlated) properties. Tempering [1] is basically a process that trades some hardness (i.e. soften) for a lot of toughness (i.e. strengthen).
[1]: https://en.wikipedia.org/wiki/Tempering_(metallurgy)