That won't do vs That's not gonna fly this time

When to use each in English, with meaning, register, and examples.

That won't do

InformalTop 3,000 (common)

That's not gonna fly this time

InformalTop 3,000 (common)
 That won't doThat's not gonna fly this time
Pronunciation🇬🇧 //ðæt woʊnt duː//🇺🇸 //ðæt woʊnt du//🇬🇧 //ðæts nɒt ˈɡɒnə flaɪ ðɪs taɪm//🇺🇸 //ðæts nɑt ˈɡɑnə flaɪ ðɪs taɪm//
MeaningThat is not acceptable.That won't be accepted or allowed now.
ExampleHe arrived late again, and I said, 'That won't do.'I know you want a day off, but that's not gonna fly this time.
RegisterInformalInformal
How commonTop 3,000 (common)Top 3,000 (common)
Collocationsthat won't do for now, that won't do at all, that won't do todayain't gonna fly, not gonna fly, gonna fly away, this plan won't fly, that idea might fly
Common mistakesConfusing with 'that doesn't work'. They are similar but have different implications., Using in overly formal settings, where more polite expressions are expected.Using 'fly' instead of 'flies'., Confusing it with similar phrases like 'that's not going to work'., Misunderstanding the meaning as literal.
Usage notesUsed informally to express disapproval or that something is inadequate. Not suitable for formal contexts.Used in casual conversations to indicate disapproval of an idea or proposal. It might not be suitable in formal contexts.

See it in real clips

That won't do
That's not gonna fly this time

Frequently asked questions: That won't do vs That's not gonna fly this time

What's the difference between That won't do and That's not gonna fly this time?

That won't do: That is not acceptable. That's not gonna fly this time: That won't be accepted or allowed now.

Can you show an example of each?

That won't do: He arrived late again, and I said, 'That won't do.' That's not gonna fly this time: I know you want a day off, but that's not gonna fly this time.

Can I use That won't do and That's not gonna fly this time interchangeably?

Not always. That won't do and That's not gonna fly this time are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.