loon
noun
[ luːn ]
• a silly or foolish person.
• "if only she weren't such a lovesick loon"
Origin:
late 19th century: from loon2 (referring to the bird's actions when escaping from danger), perhaps influenced by loony.
loon
noun
• a large diving waterbird with a sleek black or grey head, a straight pointed bill, and short legs set far back under the body; a diver.
Origin:
mid 17th century: probably by alteration of Shetland dialect loom, denoting especially a guillemot or a diver, from Old Norse.
loon
verb
• act in a foolish or desultory way.
• "he decided to loon around London"
Origin:
1960s: of unknown origin.