Fail vs I let you all down

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

Fail

Top 2,000 (common)A2verb

I let you all down

Top 3,000 (common)
Most common: Fail
 FailI let you all down
Pronunciation🇬🇧 /["/feɪl/","/feɪlz/","/feɪld/","/ˈfeɪlɪŋ/"]/🇺🇸 /["/feɪl/","/feɪlz/","/feɪld/","/ˈfeɪlɪŋ/"]/🇬🇧 //aɪ lɛt juː ɔːl daʊn//🇺🇸 //aɪ lɛt juː ɔl daʊn//
MeaningTo not succeed in doing something.I disappointed everyone.
ExampleI didn't study enough, so I knew I would fail the exam.After I missed the important meeting, I let you all down.
RegisterNeutralNeutral
How commonTop 2,000 (common)Top 3,000 (common)
CEFR levelA2-
Part of speechverb
Collocationsdismally, miserably, spectacularly, cannot, can hardly, be bound to, in, try and fail, completely, totallylet down expectations, let down a team, let down friends, let down deeply, let down completely
Antonymssucceed, prevail, triumph-
Common mistakesConfused with 'fail' and 'fail at' - remember 'fail' can stand alone., 'Failed' used incorrectly in progressive tenses - it’s typically past tense., Overusing 'fail' in positive contexts where a softer word like 'struggle' might be better.Saying 'let down' instead of 'let you all down' when referring to a group., Using 'let' in a positive context instead of acknowledging disappointment., Confusing 'let down' with other phrases like 'let go' or 'let in'.
Usage notesUse 'fail' in neutral contexts such as reports or everyday conversations. Avoid using it in overly formal situations. For failure in a job or exam, it's often directed towards the action not the person.Use this phrase when expressing regret for not meeting expectations. It's suitable in both personal and professional contexts but avoid in formal writing.

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Fail
I let you all down

Frequently asked questions: Fail vs I let you all down

What's the difference between Fail and I let you all down?

Fail: To not succeed in doing something. I let you all down: I disappointed everyone.

Which is more common: Fail and I let you all down?

Fail is the most common in everyday English.

Can you show an example of each?

Fail: I didn't study enough, so I knew I would fail the exam. I let you all down: After I missed the important meeting, I let you all down.

Can I use Fail and I let you all down interchangeably?

Not always. Fail and I let you all down 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.