The fool may try to show others he is wise, but he can’t help himself, his foolishness seeps out, as Solomon said,
Even when a fool walks along the way,
He lacks wisdom,
And he shows everyone that he is a fool.
Walk in wisdom and let the fool go about his way and people will see him for what he is.
For example, do not trouble yourself over someone who acts foolishly toward you, wondering whether others might believe his false accusations against you, because in time, people will see him for what he is.