Synonyms of the word

unserviceable

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

broken-down

• adj. which has broken down and, as a result, is no longer in working order.
• adj. not properly maintained; neglected.

inoperable

• adj. Incapable of being successfully surgically operated on.
• adj. Incapable of correct operation or function; inoperative.

nonfunctional

• adj. Not functional; useless; broken.

unrepaired

• adj. Not (yet) repaired.

unusable

• adj. Not usable.

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.