From Middle Englishfenny, fenni(“marshy, muddy; of meat: putrid, rotten; of a person: sinful, vile”),[1] from Old Englishfenniġ(“dirty; marshy, muddy, fenny”), from fen, fenn(“marsh, fen; mud”) (ultimately from Proto-Indo-European*pen-(“moist, wet; mud; swamp; water”)) + -iġ(suffix forming adjectives). The English word is analysable as fen +-y(suffix meaning ‘having the quality of’ forming adjectives).[2]
[F]or ſo many faire and Nauigable Riuers ſo neere adioyning, and piercing thorovv ſo faire a naturall Land, free from any inundations, or large Fenny vnvvholſome Marſhes, I haue not ſeene, read, nor heard of:[…]
1661, Robert Lovell, “Tetrapodologia. Of Fourfooted Beasts.”, in ΠΑΝΖΩΟΡΥΚΤΟΛΟΓΙΑ[PANZŌORYKTOLOGIA]. Sive Panzoologicomineralogia. Or A Compleat History of Animals and Minerals, Containing the Summe of All Authors, both Ancient and Modern, Galenicall and Chymicall, [...], Oxford, Oxfordshire:[…] Hen[ry] Hall, for Jos[eph] Godwin, →OCLC, page 47:
Elephant. Elephantus.[…] Their differences are according to place; ſo ſome live in fenny places, ſome on mountaines, ſome in fields, others in vvoods, &c.
It is a custom with the northern lovers to divert themselves with a song whilst they journey through the fenny moors to pay a visit to their mistresses.
A fenny gooſe, even as her fleſhe is blacker, ſtoorer, unholſomer, ſo is her feather, for the ſame cauſe, courſer, ſtoorer, and rougher, and therefore I have heard very good fletchers ſay, that the ſecond fether in ſome place is better than the pinion in other ſome.
Of the Indian Dragons there are alſo ſaid to be tvvo kindes, one of them fenny, and liuing in the Marſhes, vvhich are ſlovv of pace and vvithout combes on their heades like females:[…]
1661, Robert Lovell, “Ornithologia. Of Birds. [Brids[sic– meaning Birds] Lesse Used in Meat or Medicine.]”, in ΠΑΝΖΩΟΡΥΚΤΟΛΟΓΙΑ[PANZŌORYKTOLOGIA]. Sive Panzoologicomineralogia. Or A Compleat History of Animals and Minerals, Containing the Summe of All Authors, both Ancient and Modern, Galenicall and Chymicall, [...], Oxford, Oxfordshire:[…] Hen[ry] Hall, for Jos[eph] Godwin, →OCLC, page 181:
Godvvit. […] they are a fenny fovvl, and live of VVorms, about River banks:[…]
1718, Mat[thew] Prior, “Solomon on the Vanity of the World. A Poem in Three Books.”, in Poems on Several Occasions, London:[…]Jacob Tonson[…], and John Barber[…], →OCLC, book I (Knowledge), page 409:
The hungry Crocodile, and hiſſing Snake/ Lurk in the troubl'd Stream and fenny Brake:[…]