Other forms: preening, preens
To preen is to clean and arrange feathers with the beak. The bird preened, preening on the branch, preen its wing.
It is not vanity but maintenance: the bird spreads oil from a gland near the tail along each feather and zips the barbs back together, and a bird that cannot preen loses waterproofing and warmth. Of a person, to preen is to admire yourself openly.
1verbpreenTo clean and arrange feathers with the beak.
“The swan preened its feathers on the bank before sliding back into the river.”
preen is a grooming.
Middle English prenen, probably from pren, a pin, from the beak's action.
Proto-Indo-European
*brew- — protrusion, tip, edge
Proto-Germanic
*preunaz
Old English
prēon
Middle English
pren
English, today
preen
From Middle English pren, from Old English prēon, from Proto-Germanic preunaz (compare Icelandic prjónn (“pin, knitting-needle”), Danish pryne (“needle, eel-spear”)), of uncertain origin, but perhaps from Proto-Indo-European brew- (“protrusion, tip, edge”) (compare Lithuanian briaunà (“edge”), Albanian brez (“belt, girdle”)). Cognate with German Pfriem. The verb is from Middle English prenen, from pren (“a preen”), akin to German pfriemen.
Etymology from Wiktionary, CC BY-SA