underpants(n = noun.artifact) - an undergarment that covers the body from the waist no further than to the thighs; usually worn next to the skin;
is a kind of undergarment, unmentionable
is a part of pantyhose
has particulars: bikini pants, bloomers, drawers, knickers, pants, briefs, jockey shorts, boxers, boxershorts, drawers, shorts, underdrawers, pantie, panty, scanty, step-in, thong

underpants, n.pl. an undergarment, esp. men's, covering the lower part of the body and part of the legs.

N  clothing, investment, covering, dress, raiment, drapery, costume, attire, guise, toilet, toilette, trim, habiliment, vesture, vestment, garment, garb, palliament, apparel, wardrobe, wearing apparel, clothes, things, underclothes, array, tailoring, millinery, finery, full dress, garniture, theatrical properties, outfit, equipment, trousseau, uniform, regimentals, continentals, canonicals, livery, gear, harness, turn-out, accouterment, caparison, suit, rigging, trappings, traps, slops, togs, toggery, day wear, night wear, zoot suit, designer clothes, masquerade, dishabille, morning dress, undress, kimono, lungi, shooting-coat, mufti, rags, tatters, old clothes, mourning, weeds, duds, slippers, robe, tunic, paletot, habit, gown, coat, frock, blouse, toga, smock frock, claw coat, hammer coat, Prince Albert coat, sack coat, tuxedo coat, frock coat, dress coat, tail coat, cloak, pall, mantle, mantlet mantua, shawl, pelisse, wrapper, veil, cape, tippet, kirtle, plaid, muffler, comforter, haik, huke, chlamys, mantilla, tabard, housing, horse cloth, burnoose, burnous, roquelaure, houppelande, surcoat, overcoat, great coat, surtout, spencer, mackintosh, waterproof, raincoat, ulster, P-coat, dreadnought, wraprascal, poncho, cardinal, pelerine, barbe, chudder, jubbah, oilskins, pajamas, pilot jacket, talma jacket, vest, jerkin, waistcoat, doublet, camisole, gabardine, farthingale, kilt, jupe, crinoline, bustle, panier, skirt, apron, pinafore, bloomer, bloomers, chaqueta, songtag, tablier, pants, trousers, trowsers, breeches, pantaloons, inexpressibles, overalls, smalls, small clothes, shintiyan, shorts, jockey shorts, boxer shorts, tights, drawers, panties, unmentionables, knickers, knickerbockers, philibeg, fillibeg, pants suit, culottes, jeans, blue jeans, dungarees, denims, Levis, Calvin Klein, Calvins, Bonjour, Gloria Vanderbilt, headdress, headgear, chapeau, crush hat, opera hat, kaffiyeh, sombrero, jam, tam-o-shanter, tarboosh, topi, sola topi, pagri, puggaree, cap, hat, beaver hat, coonskin cap, castor, bonnet, tile, wideawake, billycock, wimple, nightcap, mobcap, skullcap, hood, coif, capote, calash, kerchief, snood, babushka, head, coiffure, crown, chignon, pelt, wig, front, peruke, periwig, caftan, turban, fez, shako, csako, busby, kepi, forage cap, bearskin, baseball cap, fishing hat, helmet, mask, domino, body clothes, linen, hickory shirt, shirt, sark, smock, shift, chemise, night gown, negligee, dressing gown, night shirt, bedgown, sac de nuit, underclothes, underpants, undershirt, slip, brassiere, corset, stays, corsage, corset, corselet, bodice, girdle, stomacher, petticoat, panties, under waistcoat, jock, athletic supporter, jockstrap, sweater, jersey, cardigan, turtleneck, pullover, sweater vest, neckerchief, neckcloth, tie, ruff, collar, cravat, stock, handkerchief, scarf, bib, tucker, boa, cummerbund, rumal, rabat, shoe, pump, boot, slipper, sandal, galoche, galoshes, patten, clog, sneakers, running shoes, hiking boots, high-low, Blucher boot, wellington boot, Hessian boot, jack boot, top boot, Balmoral, arctics, bootee, bootikin, brogan, chaparajos, chavar, chivarras, chivarros, gums, larrigan, rubbers, showshoe, stogy, veldtschoen, legging, buskin, greave, galligaskin, gamache, gamashes, moccasin, gambado, gaiter, spatterdash, brogue, antigropelos, stocking, hose, gaskins, trunk hose, sock, hosiery, glove, gauntlet, mitten, cuff, wristband, sleeve, swaddling cloth, baby linen, layette, ice wool, taffeta, pocket handkerchief, hanky, hankie, clothier, tailor, milliner, costumier, sempstress, snip, dressmaker, habitmaker, breechesmaker, shoemaker, Crispin, friseur, cordwainer, cobbler, hosier, hatter, draper, linen draper, haberdasher, mercer, diaper, nappy, disposable diaper, cloth diaper, Luvs Huggies, invested, habited, dighted, barbed, barded, clad, costume, shod, chausse, en grande tenue, sartorial, the soul of this man is his clothes.