Cool MateThat's a lie vs That's not true
When to use each in English, with meaning, register, and examples.
That's a lie
Common idiom
That's not true
Top 2,000 (common)
Most common: That's not true
| That's a lie | That's not true | |
|---|---|---|
| Pronunciation | 🇬🇧 //ðæts ə laɪ//🇺🇸 //ðæts ə laɪ// | 🇬🇧 //ðæts nɒt truː//🇺🇸 //ðæts nɑt tru// |
| Meaning | It's not true. | This is a way to say something is false. |
| Example | When he claimed he finished the project on time, I thought, 'That's a lie.' | When he claimed I was late, I immediately said, 'That's not true.' |
| Register | Neutral | Neutral |
| How common | Common idiom | Top 2,000 (common) |
| Collocations | tell a lie, caught in a lie, big lie | say that's not true, feel that's not true, know that's not true |
| Common mistakes | Use 'lies' instead of 'lie' when referring to multiple falsehoods., Confuse with 'lying' which refers to the act of being in a horizontal position. | Using it in very formal contexts where a gentler correction is needed., Confusing it with more polite phrases like 'I disagree' or 'That's incorrect'. |
| Usage notes | Used to express disbelief or accusation. Avoid in formal contexts. | Use this phrase when you want to correct someone. It’s commonly used in discussions but can sound confrontational, so be mindful of tone. |
See it in real clips
Frequently asked questions: That's a lie vs That's not true
What's the difference between That's a lie and That's not true?
That's a lie: It's not true. That's not true: This is a way to say something is false.
Which is more common: That's a lie and That's not true?
That's not true is the most common in everyday English.
Can you show an example of each?
That's a lie: When he claimed he finished the project on time, I thought, 'That's a lie.' That's not true: When he claimed I was late, I immediately said, 'That's not true.'
Can I use That's a lie and That's not true interchangeably?
Not always. That's a lie and That's not true 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.