LOON

loon, diver

(noun) large somewhat primitive fish-eating diving bird of the northern hemisphere having webbed feet placed far back; related to the grebes

loon

(noun) a worthless lazy fellow

addlehead, addle-head, loon, birdbrain

(noun) a person with confused ideas; incapable of serious thought

Source: WordNet® 3.1

Etymology 1

Noun

loon (plural loons)

An idler, a lout.

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

(chiefly, Scotland) A harlot; mistress.

(chiefly, Scotland) A simpleton.

(slang) A crazy or deranged person.

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

Synonyms

• (crazy person): lunatic, psycho, wacko

Etymology 2

Noun

loon (plural loons)

(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.

Synonyms

• (bird of order Gaviiformes): diver

Source: Wiktionary

Loon, n. Etym: [Scot. loun, lown, loon; akin to OD. loen a stupid man; prob. for an older lown, and akin to E. lame.]

Definition: A sorry fellow; a worthless person; a rogue.

Loon, n. Etym: [For older loom, Icel. l; akin to Dan. & Sw. lom.] (Zoöl.)

Definition: Any one of several aquatic, wed-footed, northern birds of the genus Urinator (formerly Colymbus), noted for their expertness in diving and swimming under water. The common loon, or great northern diver (Urinator imber, or Colymbus torquatus), and the red-throated loon or diver (U. septentrionalis), are the best known species. See Diver.

Source: Webster’s Unabridged Dictionary 1913 Edition