Similar word to sickish:

ailing, below par, bilious, cranky, delicate, diseased, down, dragging, faint, feeble, in poor health, indisposed, infirm, lackluster, laid-low, languid, low, mean, off-color, out of action, out of shape, pallid, peaked, peaky, pining, poorly, rocky, run-down, seedy, sickish, unhealthy, wan, weak