General "useless":
* Inutile: This is the most common and direct translation of "useless."
* Inutile de dire: This means "needless to say," implying that something is obvious or unnecessary.
More specific "useless":
* Inopérant: This means "inoperative" or "not working," suggesting something is useless because it doesn't function.
* Improductif: This means "unproductive," implying something is useless because it doesn't yield results.
* Futile: This is a more formal word for "useless" and often conveys a sense of hopelessness.
Informal "useless":
* Inutile: This is still the most common and can be used in informal settings.
* Bon à rien: This means "good for nothing" and is a more colloquial and slightly derogatory way to say "useless."
Examples:
* This tool is inutile. (This tool is useless.)
* It's inutile de dire that you're wrong. (Needless to say, you're wrong.)
* The machine is inopérant. (The machine is not working.)
* This plan is improductif. (This plan is unproductive.)
* Their efforts were futiles. (Their efforts were useless.)
* He's a bon à rien. (He's a good-for-nothing.)
The best way to choose the right word depends on the situation and the desired level of formality.