Definition of "loon" in English

noun

1. (slang) A crazy or deranged person; a lunatic.

2. (obsolete) An idler, a lout.

3. (chiefly Scotland, Ulster) A boy, a lad.

4. (chiefly Scotland) A harlot; mistress.

5. (chiefly Scotland) A simpleton.

6. (Ireland, historical) An English soldier of an expeditionary army in Ireland.

7. (traffic engineering) A round area of pavement that protrudes from one side of a road to accommodate turning vehicles with a wide turning circle.

noun

1. (US, Canada) Any of various birds, of the order Gaviiformes, of North America and Europe that dive for fish and have a short tail, webbed feet and a yodeling cry.