The noun 死人 (sǐrén) means 'dead person' or 'casualty.' It is a direct and colloquial term composed of 死 (to die) and 人 (person). In some contexts, particularly when used as a verb-object phrase, it can mean 'to have deaths' or 'people die,' as in 会死人 (someone could die).
那个地方发生了事故,听说死人了。
Nà ge dìfang fāshēng le shìgù, tīngshuō sǐ rén le.
An accident happened at that place; I heard someone died.
警察赶到现场时发现了一个死人。
Jǐngchá gǎn dào xiànchǎng shí fāxiàn le yí gè sǐ rén.
When the police arrived at the scene, they found a dead person.
天气这么热,不开空调会死人的。
Tiānqì zhème rè, bù kāi kōngtiáo huì sǐ rén de.
It's so hot; without air conditioning, people could die.