(a.) Having no spine.

abulic adrift afloat afraid alternating amorphous anemic asthenic bloodless capricious changeable changeful chicken cowardly craven dastardly debilitated desultory deviable dizzy drooping droopy dull eccentric effete emasculate erratic etiolated faint fainthearted faintish fast and loose fearful feeble feebleminded fickle fitful flabby flaccid flickering flighty flitting floppy fluctuating forceless frail freakish giddy gone gutless imbecile impetuous impotent impulsive inadequate inconsistent inconstant indecisive ineffective ineffectual infirm invertebrate irregular irresolute irresponsible languid languorous lily-livered limber limp listless lustless marrowless mazy mercurial moody nerveless pithless pliable pooped powerless pusillanimous rambling restless roving rubbery sapless scatterbrained shapeless shifting shifty shuffling sinewless slack soft spasmodic spiritless squeamish strengthless timid timorous unaccountable uncertain uncontrolled undependable undisciplined unfixed unhardened unnerved unpredictable unreliable unrestrained unsettled unstable unstable as water unstaid unsteadfast unsteady unstrung vacillating vagrant variable vicissitudinary vicissitudinous volatile wandering wanton wavering wavery wavy wayward weak weak-kneed weak-minded weak-willed weakly whimsical white-livered wishy-washy yellow