A colorless, poisonous alkaloid, C10H14N2, derived from the tobacco plant and used as an insecticide. It is the substance in tobacco to which smokers can become addicted.

• 尼古丁无色有毒生物碱，C10H14N2，从烟草中提取被用作杀虫剂，它是烟草中致使吸烟者上瘾的物质