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 enjoys telling or playing jokes
a person who does something thoughtless or annoying; "some joker is blocking the driveway"
a mischievous supernatural being found in the folklore of many primitive people; sometimes distinguished by prodigious biological drives and exaggerated bodily parts