What is Fool ?
Fool is (noun) 1. a stupid person You fool! Why didn’t you put the brakes on? I was a fool to think that I could make her change her mind. to make a fool of yourself to behave in a silly way 2. a type of sweet food made from fruit and cream She made some gooseberry fool. (verb) 1. to fool about or around to play around in a silly way Stop fooling around with that knife you’re going to have an accident. 2. to trick someone They fooled the old lady into letting them into her house. You can’t fool me I know you’re not really ill. you could have fooled me I find it hard to believe She says she did her best well, you could have fooled me! (adj) stupid (informal.)
source: Easier English, Student Dictionary Upper Intermediate Level