noun
crybaby
A person who cries easily or often; often used teasingly or affectionately.
弟はすぐ泣くから、みんなに泣き味噌と呼ばれている。
My little brother cries easily, so everyone calls him a crybaby.
そんなことで泣くなよ、泣き味噌。
Don't cry over something like that, you crybaby.
泣き虫 is a more common and slightly stronger word for 'crybaby', while 泣き味噌 can sound a bit softer or more old-fashioned.
Compound of 泣き (crying) and 味噌 (miso, soybean paste). The exact derivation is uncertain; it may be a playful or metaphorical use of 味噌, perhaps likening a crybaby to something soft or easily broken down.