noun
Informal, often derogatory or familiar term for a person, typically male. Can be used among close friends or to look down on someone.
あのやつ、また遅刻だよ。
That guy is late again.
変なやつだな。
He's a weird fellow.
noun
Colloquial use to refer to an object or thing, often with a rough or dismissive tone. Common in casual speech.
そのやつ、ちょっと見せて。
Let me see that thing.
このやつ、もう壊れてるよ。
This thing is already broken.
pronoun
Pronoun used to refer to a third person in a derogatory or very familiar way. Can be used for both genders, but often implies contempt or close familiarity.
やつは何も知らないくせに。
He doesn't know anything, and yet...
やつに任せたらダメだ。
Don't leave it to him/her.
Originally a noun meaning 'servant' or 'guy', derived from Old Japanese. The derogatory/familiar usage developed over time. The exact historical derivation is uncertain.