nicotine

/ˈnɪkətiːn/

IPA: /N IH1 K AH0 T IY0 N/

noun
  1. 1

    An alkaloid (C10H14N2), commonly occurring in the tobacco plant. In small doses it is a habit-forming stimulant; in larger doses it is toxic and is often used in insecticides.

  2. 2

    Tobacco, cigarettes

    He is addicted to nicotine.

Source: https://en.wiktionary.org/wiki/nicotine