faulty

/ˈfɔːlti/
adjective
  1. Not working correctly or having a defect; imperfect.
    • The mechanic found a faulty wire in the car's engine.
    • A faulty smoke detector can be dangerous in a fire.
    • We returned the faulty blender because it wouldn't turn on.
  2. Containing mistakes or errors; incorrect.
    • His faulty reasoning led to the wrong conclusion.
    • Faulty data caused the experiment to fail.
    • The student corrected the faulty grammar in her essay.