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Definition of loosejaw

loosejaw

/ˈluːsˌdʒɔː/
loose · jaw
Plural:loosejaws
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loosejaw Lexical Profile

• noun

1

Any of several small, predatory deep-sea fishes of the genus Malacosteus, characterized by a large, specialized lower jaw that lacks an interconnecting membrane, allowing it to snap shut rapidly without water resistance to catch prey.

Example

"The marine biologist explained how the loosejaw utilizes red bioluminescence to illuminate unsuspecting prey before striking with its remarkable mouth structure."

Synonyms
View all synonyms for loosejaw

• Nearby Words

loopy
loose
loosebox
loosejaw
loosely
loosen
looseness

Word Origin & Etymology

A descriptive compound of the English words 'loose' and 'jaw', directly referring to the uniquely hinged, open-floor lower jaw of this deep-sea fish.

Usage Trend

Historical frequency of usage in published text.

180019102020
Data source: Google Books Ngram Viewer

Cite this Entry

Wordmom. (2026). Definition of Loosejaw. In Wordmom Dictionary. Retrieved Nov 5, 2026, from https://wordmom.com/dictionary/loosejaw
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