(of an action) of no use; having no effect

hopeless, pointless

doing no work; not active or in use; to spend (time) in a lazy manner

worthless, ineffective

of small size, value, importance etc

petty

not producing the effect(s) desired

useless

having little or no value, use, meaning or importance

not important; of no consequence

not valid; invalidate; weak or disabled because of illness or injury; suitable for invalid persons

worthless; unfounded

(of) an animal without a backbone or spinal column, e.g. insects, worms

weak, useless

expressing 'no', 'not', a refusal; lacking commitment, enthusiasm; (of number or amount) less than zero

bad, contradictory

seeming to be right or true but not really so

misleading

of little value or importance; ordinary (and so dull)

not important

not important

of no real worth, value

zip

of no real worth, value