Synonyms of the word

useless

• adj. Without use or possibility to be used.
• adj. Unhelpful, not useful; pointless (of an action).
• adj. (pejorative, of a person) good-for-nothing; not dependable.
• adj. (colloquial, of a person) unable to do well at a particular task or thing. Useless is mildly insulting.

futile

• adj. Incapable of producing results; useless; not successful; not worth attempting.

ineffective

• adj. not having the desired effect; ineffectual.
• adj. lacking in ability; incompetent or inadequate.

ineffectual

• adj. unable or insufficient to produce effect; futile.
• adj. worthless.
• adj. weak, indecisive; lacking forcefulness.

inutile

• adj. (obsolete) useless; unprofitable.

otiose

• adj. Resulting in no effect.
• adj. Reluctant to work or to exert oneself.
• adj. Having no reason for being (raison d’être); having no point, reason, or purpose.

unavailing

• adj. useless, fruitless, futile.

unprofitable

• adj. Not making a profit.

unserviceable

• adj. unusable.
• adj. not working (machinery, etc).
• adj. impractical.

unusable

• adj. Not usable.