To Forge, To Temper, To Train, To Discipline
transitive verb, ichidan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means forge and the verb vocab version is to forge and to temper.
きたえる
To forge something, you need to have your kit (きた) with you. Without it, you won't be doing any forging at all.
生まれたての頃からミッチリ鍛えたおかげで、息子は今ピアノの天才児と呼ばれています。
Thanks to the strict training I’ve given him since birth, my son is now called a child prodigy at piano.