gudgeon

Etymology 1

The noun is derived from Late Middle English gojoun [and other forms], from Old French gojon, goujon (“gudgeon”), from Late Latin gōbiōnem, the accusative of gōbiō, the augmentative of Latin gōbius (“gudgeon”), from Ancient Greek κωβῐός (kōbiós, “fish of the gudgeon kind”), probably of Semitic origin. The English word is a doublet of goby and goujon. The verb is derived from the noun.

noun

1. A small freshwater fish, Gobio gobio, that is native to Eurasia.
2. (Canada) Cottus bairdii, more widely known as mottled sculpin.
3. (Australia) Any of various similar small fish of the family Eleotridae, often used as bait.
   The southern purple-spotted gudgeon [Mogurnda adspersa] can be hard to find. Although colourful, they are thin and only grow up to 12 centimetres. 5 October 2012, Nicola Gage, “Murray Showing Signs of Recovery”, in ABC News, Sydney, N.S.W., archived from the original on 2019-11-01
4. Other fish, similar in appearance, principally in families Butidae and Eleotridae, but also in others.
5. (figurative, archaic) A person apt to take the bait; one easily cheated or duped; also, an idiot.
   The Doctor now obeys the Summons, / Likes both his Company, and Commons; / Diſplays his Talent, ſits till Ten; / Next Day invited, comes again; / Soon grows Domeſtick, ſeldom fails, / Either at Morning, or at Meals; / Came early, and departed late: / In ſhort, the Gudgeon took the Bait. 1713, Jonathan Swift, “Horace, Epistle VII. Book I. Imitated and Addressed to the Earl of Oxford, in the Year 1713”, in Miscellanies. The Last Volume, London: […] Benjamin Motte,[…], published 1733, →OCLC, lines 73–80, page 149
   "Don't be a gudgeon," she grumbled, tugging at the dress much more fiercely than was necessary. "If this works as you say it will, nobody will notice me." 2004, Robert Jordan, “Making Use of Invisibility”, in New Spring, New York, N.Y.: Tor Books, Tom Doherty Associates, page 298
6. (figurative, archaic) Something used to lure">lure or tempt; bait, a lure">lure.

verb

1. (transitive, archaic) To deprive (someone) fraudulently; to cheat, to dupe.
2. (intransitive, archaic) To take the bait; to be defrauded or duped.

Etymology 2

From Middle English gojoun (“metal fitting with a ring at one end”) [and other forms], from Old French goujon (“dowel; pin”) [and other forms], from gouge (“gouge (tool)”) + -on (suffix forming diminutives). Gouge is derived from Late Latin gulbia, gubia (“chisel”), ultimately from Proto-Celtic *gulbā, *gulbīnos (“beak, bill”).

noun

1. (also attributively) A circular or cylindrical fitting, often made of metal, into which a pin or pintle fits to create a hinge or pivoting joint.
2. (nautical, specifically) In a vessel with a stern-mounted rudder: the fitting into which the pintle of the rudder fits, allowing the rudder to swing freely.