Underclothing (noun)

Garments worn next to the skin and under other garments, typically for warmth or modesty.

Origin:

The word "underclothing" is derived from the word "under" and "clothing" which means clothes worn next to the skin and under outer garments.

Examples:

1. She changed into her underclothing before bed.
2. I always wear underclothing made of cotton because it's breathable.
3. I forgot to pack my underclothing for my trip.
4. The store had a wide variety of underclothing for men and women.
5. He wore a tank top as his underclothing, but he put on a shirt to go out.