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