The crossword solution for the term UNFOOLED BY is ONTO, which is a four-letter word. ONTO is a preposition that means 'to a position on or over; upon; ONTO; on top of.' It is often used to indicate movement from one place to another. It can also be used to describe a situation in which someone is not fooled by something. In this context, it implies that someone is aware of the truth and is not deceived by false information.