feeble

(s) pathetically lacking in force or effectiveness
- a feeble excuse
- a lame argument
lame,
(s) lacking strength or vigor
- damning with faint praise
- faint resistance
- feeble efforts
- a feeble voice
faint,
(s) lacking bodily or muscular strength or vitality
- a feeble old woman
- her body looked sapless
debile, infirm, sapless, weakly, decrepit, rickety, weak,
(s) lacking strength
- "a weak, nerveless fool, devoid of energy and promptitude"- Nathaniel Hawthorne
nerveless,

lame faint debile infirm sapless weakly decrepit rickety weak nerveless

feebly

feebleminded feeblemindedness feebleness