Origin: Latin suffix -ment
Garment has 4 different meanings across 2 categories:
A single item of clothing.
"She carefully folded her favorite wool garment before placing it in the drawer."
In plain English: A garment is any piece of clothing that you wear on your body to cover it up.
"She hung her favorite summer garment on the back of the door to dry out from the rain."
To clothe in a garment.
"The tailor carefully garmented the young model in her new evening gown before she walked onto the runway."
The word garment comes from the Middle English form of an Old French verb meaning to protect or clothe. It ultimately traces back through a Germanic root related to warding someone off before entering English with its current sense of clothing.