dun

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An almost neutral brownish gray to dull grayish brown.
• noun A horse of this color.
• noun A mayfly in its earliest adult stage.
• noun An fishing fly that imitates such an insect.
• transitive verb To importune (a debtor) for payment.
• noun One that duns.
• noun An importunate demand for payment.

from The Century Dictionary.

• noun One who duns; an importunate creditor, or an agent employed to collect debts.
• noun A demand for the payment of a debt, especially a written one; a dunning-letter: as, to send one's debtor a dun.
• To make of a dun or dull-brown color.
• Especially To cure, as cod, in such a manner as to impart a dun or brown color. See dunfish.
• To become of a dun color.
• To make a loud noise; din.
• To demand payment of a debt from; press or urge for payment or for fulfilment of an obligation of any kind.
• noun A hill; a mound; a fortified eminence.
• Of a color partaking of brown and black; of a dull-brown color; swarthy.
• Dark; gloomy.
• noun A familiar name for an old horse or jade: used as a quasi-proper name (like dobbin).
• noun A dun-colored natural or artificial fly used in angling: as, the pale-olive dun, made with a body of hair from the polar bear; goose-dun, with a body of gray goose-pinion; blue dun, with a body of pale mole-fur.

from the GNU version of the Collaborative International Dictionary of English.

• verb To ask or beset (e.g., a debtor), for payment; to urge importunately.
• adjective Of a dark color; of a color partaking of a brown and black; of a dull brown color; swarthy.
• adjective (Zoöl.) the hooded crow; -- so called from its color; -- also called hoody, and hoddy.
• adjective (Zoöl.) the goosander or merganser.
• transitive verb To cure, as codfish, in a particular manner, by laying them, after salting, in a pile in a dark place, covered with salt grass or some like substance.
• noun A mound or small hill.
• noun One who duns; a dunner.
• noun An urgent request or demand of payment.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun countable A newly hatched, immature mayfly.
• phrase Eye dialect spelling of don't.
• noun A valley in the Himalayan foothills, e.g. Dehra Dun.
• verb informal Eye dialect spelling of done: simple past tense and past participle of do.
• noun uncountable A brownish grey colour.
• adjective Of a brownish grey colour.
• noun countable A collector of debts.
• verb transitive To ask or beset a debtor for payment.
• verb transitive To harass by continually repeating e.g. a request.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb treat cruelly
• verb cure by salting
• verb make a dun color
• noun horse of a dull brownish grey color
• adjective of a dull greyish brown to brownish grey color
• noun a color or pigment varying around a light grey-brown color
• verb persistently ask for overdue payment