Here are the definitions matched to the correct terms:
1. **Carcinogen** - a cancer-causing substance.
2. **Addictive drug** - a substance that causes physiological or psychological dependence.
3. **Nicotine** - the addictive drug found in tobacco leaves.
4. **Stimulant** - a drug that increases the action of the central nervous system, the heart, and other organs.
5. **Smokeless tobacco** - tobacco that is sniffed through the nose, held in the mouth, or chewed.
6. **Tar** - a thick sticky dark fluid produced when tobacco burns.
7. **e-cigarette** - electronic cigarette.
8. **Vaping** - inhaling vapor created by an electronic cigarette.
9. **Carbon monoxide** - a colorless, odorless, and poisonous gas.