tranquilize

verb4

1. •
   To calm (a person or animal) or put them to sleep using a tranquilizer dart.

   • The escaped lion was finally tracked down, tranquilized, and safely returned to the zoo.
2. •
   To dart (a person or animal) with a sedative

   • The bear should go down several minutes after being tranquilized.
3. •
   (literary) To make (something or someone) tranquil.

   • […] with words of sweetest kindness and consolation, he soothed and tranquilised me. — 1779
4. •
   (no longer used, rare) To become tranquil.