All for naught is an idiom that means "all for nothing", e.g. Kate didn't get the promotion, and she felt her hard work was all for naught. People often confuse all for naught with homophones for naught. Sometimes, people write "all for not" because "not" is similar to "nothing".

What does it mean for naught?

: nothing Their efforts came to naught. It was all for naught.

What does go for naught mean?

old-fashioned, US. : to be unsuccessful : to not achieve what something was intended to do All our efforts went for naught.