n.
  - a thing said to cause amusement. 
▸a trick played for fun.
 - informal a ridiculously inadequate person or thing.
 
v.
 make jokes. 
▸archaic poke fun at.
 
  Phrase
  
    - be no joke
 informal be a serious or difficult matter.  - be beyond a joke
 informal be serious or worrying. 
   
  Derivative
  
    - joking adj.
  - jokingly adv.
 
   
  Etymology
  C17: perh. from L. jocus ‘jest, wordplay’.