Proverbs 26:4-5

Do not answer a fool according to his folly, Lest you also be like him. Answer a fool according to his folly, Lest he be wise in his own eyes.
(Proverbs 26:4-5)

Some different translations/ideas

Don't make a fool of yourself by answering a fool. But if you answer any fools, show how foolish they are, so they won't feel smart.
(Proverbs 26:4-5)

If you answer a silly [stupid--ed] question, you are just as silly [stupid--ed] as the person who asked it. Give a silly [stupid--ed] answer to a silly [stupid--ed] question, and the one who asked it will realize that he's not as smart as he thinks. (Proverbs 26:4-5)

Barnes writes:

Two sides of a truth. To “answer a fool according to his folly” is in Pro_26:4 to bandy words with him, to descend to his level of coarse anger and vile abuse; in Pro_26:5 it is to say the right word at the right time, to expose his unwisdom and untruth to others and to himself, not by a teaching beyond his reach, but by words that he is just able to apprehend. The apparent contradiction between the two verses led some of the rabbis to question the canonical authority of this book. The Pythagoreans had maxims expressing a truth in precepts seemingly contradictory.