fee·ble / ˈfēbəl/ • adj. (-bler, -blest) lacking physical strength, esp. as a result of age or illness: my legs are very feeble after the flu. ∎  (of a sound) faint: his voice sounded feeble and far away. ∎  lacking strength of character: she overreacted in such a feeble, juvenile way. ∎  failing to convince or impress: a feeble excuse.DERIVATIVES: fee·ble·ness n.fee·bly / ˈfēb(ə)lē/ adv.ORIGIN: Middle English: from Old French fieble, earlier fleible, from Latin flebilis ‘lamentable,’ from flere ‘weep.’

feeble XII. — AN., OF. feble, var. of fieble (mod. faible), later forms of fleible :- L. flēbilis that is to be wept over, (hence in Rom.) weak, f. flēre weep; see -BLE.
Hence feebly XIII.