Unbutton (verb)

To unfasten the buttons of a garment.

Origin:

From the old english word "unbuton" which means remove a button, open a fastening.

Examples:

1. He unbuttoned his shirt and sat down.
2. She unbuttoned her coat before entering the house.
3. He unbuttoned his pants before sitting down.
4. I unbuttoned my dress to change.
5. He unbuttoned his shirt and revealed a white T-shirt underneath.