Better to remain silent and be thought a fool than to speak out and remove all doubt.
A fool is a person who acts in any way that is unwise, silly, or that may not be the best possible choice. If you are made a fool of then you will look like a person who does not always make smart decisions. If you are trying to fool someone, such as playing a prank on April Fool's Day, then you are making them the object of a joke or prank. If you stay silent then people may suspect that you are a fool but they will not have proof of this.