Word History: Its source, the Latin word follis, meant "a bag or sack, a large inflated ball, a pair of bellows." Users of the word in Late Latin, however, saw a resemblance between the bellows or the inflated ball and a person who was what we would call "a windbag" or "an airhead." The word, which passed into English by way of French, is first recorded in English in a work written around the beginning of the 13th century with the sense "a foolish, stupid, or ignorant person."
1. One who is deficient in judgment, sense, or understanding.
2. One who acts unwisely on a given occasion: I was a fool to have quit my job.
3. One who has been tricked or made to appear ridiculous; a dupe: They made a fool of me by pretending I had won.
4. A member of a royal or noble household who provided entertainment, as with jokes or antics; a jester.
5. A dessert made of stewed or puréed fruit mixed with cream or custard and served cold.
How did this word come to mean both someone who may be unwise, or foolish, and a dessert?
To be fooled, to be tricked; this very much links to a previous word.. deceit to decieve is to fool is it not?