adjective

lacking physical strength, especially as a result of age or illness.

by now, he was too feeble to leave his room

weak,weakly,weakened,puny,wasted,frail,infirm,delicate,sickly,ailing,unwell,poorly,failing,helpless,powerless,impotent,enfeebled,enervated,debilitated,incapacitated,effete,decrepit,doddering,doddery,tottering,tottery,shaky,trembling,trembly,shilpit,etiolated