The words quiet (two syllables) and quite (one syllable) are frequently confused.
Quiet! Please be quite. Quiet!
I encountered this bit of dialogue in a mystery published by W.W. Norton. A character is being kidnapped and the words are spoken by one of the kidnappers. Obviously all three words are meant to be quiet.
Quiet can be used as an adjective meaning “of little activity,” or as a noun meaning “tranquility” or “silence.”
After lunch the children enjoyed an hour of quiet play. (adjective)
We enjoyed the quiet of the countryside. (noun)
Quite is an adverb and has the sense of “totally” or “completely.”
She was quite exhausted after the warm-up exercise.
Quiet can also be used as a verb meaning “to cause to be quiet.”
The man behind us shouted “Quiet down, can’t you?”
The leader quieted the protesters so the mayor could be heard.
Note: the words “quieten” and “quietened” are not standard American usage.