Definition of stale :
tedious, trite, arid, high, colorless, dull, ho-hum, blase, unenthusiastic, spoilt, dried, shopworn, restless, warmed-over, clichéd, inedible, obligatory, fed up, taste, hard, unpalatable, dreary, bored, mawkish, insensate, dry, weary, stereotypical, moldy, rancid, nasty, tired, mothy, monotonous, stereotypic, cold, maggoty, ratty, stupid, cobwebby, inhuman, trivial, wearying, overworked, platitudinous, tame, limp, corny, cliché, mouldy, old, uninteresting, well-worn, tiring, funky, mind-numbing, icky, malodorous, hack, sour, listless, bromidic, overused, wilted, numbing, boring, moth-eaten, fetid, hackneyed, tiresome, platitudinal, slow, drudging, world-weary, stereotyped, solid, ponderous, commonplace, apathetic, bad, drab, spoiled, usual, smelly, threadbare, timeworn, addled, monochromatic, jading, indifferent, leaden, acrid, musty, day-old, worn-out, frigid, excite, heavy, cold-blooded, fusty, humdrum, pedestrian, dust-covered, uninspired, shabby, flyblown, unexciting, wearisome, hackney, stodgy, stuffy, frowzy, tatty, dusty
tasteless (part of speech: adjective)
- Its pop- corn gets stale. - "Fairy Prince and Other Stories", Eleanor Hallowell Abbott.
- All the stale arguments were brought forth, and had to be joined in with unmoved faces. - "The Dark Flower", John Galsworthy.
- Sure, there wasn't anything for him to stale, your honor, barrin' the birds and the geran'ums, and- No, no, I understand. - "Lady Audley's Secret", Mary Elizabeth Braddon.