Colorless

Adverbs for Colorless
monotonously; dully; cheerlessly; wanly; pallidly; neutrally; dismally; drearily; discouragingly; grievously;  sorely;  sadly; utterly; piteously; deplorably; pathetically; cruelly; wretchedly; singularly; oppressively; hopelessly; dishearteningly; needlessly; horribly; unpleasantly.

Thesaurus
achromatic, achromic, aloof, anemic, arid, ashen, ashy, barren, blah, blanched, bland, blank, bled white, bloodless, blurry, boring, cadaverous, characterless, chloranemic, cold, dead, deadly pale, deathly pale, detached, dim, dimmed, dingy, discolored, disinterested, dismal, dispassionate, doughy, drab, draggy, drearisome, dreary, dry, dryasdust, dull, dusty, effete, elephantine, empty, etiolated, exsanguinated, exsanguine, exsanguineous, fade, faded, faint, fallow, feeble, flat, ghastly, gray, haggard, hazy, heavy, ho-hum, hollow, hueless, hypochromic, impersonal, inane, inexcitable, insipid, jejune, lackluster, leaden, lifeless, livid, low-spirited, lurid, lusterless, mat, mealy, milk-and-water, muddy, namby-pamby, neutral, obscure, pale, pale as death, pale-faced, pallid, pasty, pedestrian, plodding, pointless, poker-faced, poky, ponderous, prosaic, prosy, remote, sallow, sickly, slow, solemn, spiritless, sterile, stiff, stodgy, stuffy, superficial, tallow-faced, tasteless, tedious, toneless, uncolored, unimaginative, uninspired, uninteresting, unlively, vacuous, vague, vapid, wan, washed out, washed-out, waxen, weak, whey-faced, white, wishy-washy, withdrawn, wooden