1. Serve as the inciting cause of
   "The controversial post instigated a heated debate";
   - prompt, inspire
    
2. Provoke or stir up
   "instigate a riot";
   - incite, set off, stir up

Derived forms: instigating, instigated, instigates

Type of: cause, get, have, induce, make, provoke, stimulate

Encyclopedia: Instigate