vapid

common, commonplace, ordinary, tepid, unexceptional, unsurprising

arid, boring, colorless, drab, dreary, drudging, dry, dull, dusty, flat, heavy, ho-hum, humdrum, jading, jejune, leaden, mind-numbing, monochromatic, monotonous, numbing, old, pedestrian, ponderous, slow, stale, stodgy, stuffy, stupid, tame, tedious, tiresome, tiring, uninteresting, wearisome, weary, wearying

aseptic, barren, blah, dullish, pleasureless, prosaic, prosy, soggy, spiritless

blank, earthbound, gray (also grey), inanimate, pallid, pedantic, sterile, suspenseless, undramatic, uneventful, unexciting, unimaginative, uninspiring, unnewsworthy, unrewarding, unsensational, unspectacular

longsome

palling

cumbersome, lumbering, plodding, poky (or pokey)