縮む
ちぢむ · chidimu · JLPT N2 · verb-godan
to shrink
👕 縮 = 糸 (thread) + 宿 (sound: shuku); a thread bunched up tight gets shorter, so it shrinks
The kanji 縮 contains 糸, meaning thread, and 宿, which gives the reading shuku. Wool sweaters that shrink in a hot wash are the everyday case of ちぢむ: the fibres bunch up and the garment gets shorter.