flaw

Noun

• an imperfection in a plan or theory or legal document that causes it to fail or that reduces its effectiveness

• defect or weakness in a person's character
  • he had his flaws, but he was great nonetheless
    

• an imperfection in an object or machine
  • a flaw caused the crystal to shatter
    
  • if there are any defects you should send it back to the manufacturer
    

Verb

• add a flaw or blemish to; make imperfect or defective

Related words

• Synonyms: 
  defect , fault , blemish