Gloves
noun
A hand sack is a sack for your hands... better put, these are gloves.
The readings are both the kun'yomi vocab readings, so think of 手 and 袋 as individual words, put together to make hand sacks. Watch out for the rendaku.
どうして裸んぼで手袋だけはめて走り回ってるの？あんたは本当に馬鹿ね。
Why are you running around naked with only gloves on? You’re such an idiot!