ailing

bedfast, bedridden

delicate, fragile, frail

dying, fading, incurable, moribund

challenged, debilitated, incapacitated, lame

decrepit, enfeebled, feeble, infirm, weak, weakened, worn-out

ill, indisposed, peaked, poorly, run-down, sick, unhealthy, unsound, unwell

lousy, sickish

nauseated, nauseous, qualmish, queasy (also queazy), squeamish

airsick, carsick, seasick

dizzy, light-headed, shaky, woozy

achy, feverish

diseased, disordered

decrepit, feeble, fragile, frail, infirm, invalid, sickly, weak, weakly

afflicted, troubled

challenged, debilitated, disabled, halt, incapacitated, lame

hypochondriac, hypochondriacal