This is the 10th most frequent Armenian word.
չի
"չի" = "is not" / "does not" / "no" (third person singular negative particle)
In this sentence, "չի" is used to negate the verb, indicating that the action of going has not occurred.
Նա չի գնացել դպրոց:
He/She hasn't gone to school.
Here, "չի" is used to negate the adjective "new," characterizing the car as not being new.
Ավտոմեքենան չի նոր է:
The car is not new.
In this example, "չի" negates the adjective "warm," giving information about the state of the weather.