repellent

Short definition from Wiktionary

Adjective

1. 1
   Repulsive, inspiring aversion.
2. 2
   Resistant or impervious to something.
3. 3
   Tending or able to repel; driving back.

Noun

1. 1
   A substance or solution used to repel insects, dangerous animals, or other pests.
2. 2
   A substance or treatment for a fabric etc to make it impervious to something.
3. 3
   Someone or something that repels.