毛衣(máo yī) - jumper, sweater in Mandarin

毛衣 (máoyī) is a jumper, or sweater if you prefer the American word: 毛 (máo) means wool or fur, and 衣 (yī) is clothing, so the word literally names it as a "wool garment", even though modern ones are often knitted from acrylic rather than real wool.

It is a layer worn under a coat or jacket rather than instead of one: on a cold day you might wear 毛衣 (máoyī) under 大衣 (dàyī), an overcoat, or 夹克 (jiākè), a jacket. The verb 织 (zhī), to knit, comes up often with this word, since hand-knitted jumpers from a grandparent are a real cultural fixture.

The measure word is 件 (jiàn): 一件毛衣 (yí jiàn máoyī), one jumper.