生意 (shēngyi) is a noun meaning "business" or "trade." It refers to commercial activity in general and is commonly used in everyday expressions like 做生意 (zuò shēngyi, "to do business") and 生意很好 (shēngyi hěn hǎo, "business is good").
他在市中心做生意,开了一家小店。
Tā zài shì zhōngxīn zuò shēngyì, kāi le yī jiā xiǎo diàn.
He does business in the city center and opened a small shop.
最近生意不太好,客人越来越少了。
Zuìjìn shēngyì bù tài hǎo, kèrén yuè lái yuè shǎo le.
Business hasn't been great lately — there are fewer and fewer customers.
她很有头脑,做什么生意都能赚钱。
Tā hěn yǒu tóunǎo, zuò shénme shēngyì dōu néng zhuànqián.
She's very sharp — she can make money in any business.