To Amass
To Store Up, To Lay In Stock, To Grow A Mustache
transitive verb, ichidan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means amass and the verb vocab version is to amass.
蓄える means to gradually accumulate something to store up. So you can use 蓄える for storing up resources or knowledge, or even for growing a mustache or beard!
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
You need to amass things, so you take one (たくわ) and put it aside, then take one more and put it aside again. Repeat this process of taking one over and over and you’ll quickly store up lots of things.
彼はとても立派な口髭を蓄えています。
He’s growing such a splendid mustache.