fool1
  
  n.
  - a person who acts unwisely. 
▸archaic a person who is duped or imposed on.
 - historical a jester or clown, especially one retained in a royal or noble household.
 
v.
  - trick, deceive, or dupe.
 - 
(usu. fool about/around)
 act in a joking or frivolous way. 
▸
(fool around)
 chiefly N. Amer. engage in casual or extramarital sex.
 
adj.
 N. Amer. informal foolish or silly.
 
  Phrase
  
  Derivative
  
  Etymology
  ME: from OFr. fol ‘fool, foolish’, from L. follis ‘bellows, windbag’, by extension ‘empty-headed person’.
 
  
    
fool2
  
  n.
 chiefly Brit. a cold dessert made of puréed fruit mixed or served with cream or custard.
 
  Etymology
  C16: perh. from fool1.