joker

Noun

• a playing card that is usually printed with a picture of a jester

• an inconspicuous clause in a document or bill that affects its meaning in a way that is not immediately apparent
  • when I demanded my money he showed me the joker in the contract
    

• a person who does something thoughtless or annoying
  • some joker is blocking the driveway
    

• a person who enjoys telling or playing jokes

Related words

• Synonyms: 
  turkey , jokester