simple past tense and past participle of keep
"She kept her promise to return the library books by Friday."
In plain English: To keep something means to hold onto it so you do not give it away, lose it, or let it go.
"She kept her promise to visit every weekend."
Usage: Use "kept" to describe an action that was completed in the past or to indicate a state resulting from a previous decision, such as "She kept the secret." It functions as both the simple past tense and the past participle of the verb "keep."
Kept comes from the Old English word cēpte, which carried the same meaning as the modern verb. It traveled into English through Middle English before settling in its current form.