What is shorter when it is longer and longer when it is shorter; also bigger when it is smaller and smaller when it is bigger?

A word. LONGER is shorter than SHORTER, and SMALLER is bigger than BIGGER.

Richard Lederer and Gary Hallock devised this puzzling sentence, which is best read aloud:

What is a four-letter word for a three-letter word which has five letters yet is still spelled with three letters, while it has only two and rarely has six and never is spelled with five?

It’s not a question, but a statement. Capitalize WHAT, FOR, WHICH, YET, IT, RARELY, and NEVER.