Definition from Wiktionary, the free dictionary
- Without use or possibility to be used.
- This fork has prongs that are bent. It's useless now.
- Unhelpful, not useful; pointless (of an action).
- I think it's useless to keep this discussion going. It's like talking to a wall.
- I tried my best to make him quit smoking, but my efforts were useless. He now smokes six packs a day.
- (pejorative, of a person) good-for-nothing; not dependable.
- Bill never mows the lawn, takes out the trash or anything. He's useless, but I love him anyways.
- (colloquial, of a person) unable to do well at a particular task or thing. Useless is mildly insulting.
- My brother is useless at most computer games, but he is an awesome PS2 player.
- Why do you keep trying? You're obviously useless at it.
Derived terms 
unable to do well