Fat one cannot know vs Ignorance

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

Fat one cannot know

InformalBeyond 10,000 (less common)

Ignorance

Top 2,000 (common)C1noun
Most formal: IgnoranceMost common: Ignorance
 Fat one cannot knowIgnorance
Pronunciation🇬🇧 //fæt wʌn ˈkænɒt nəʊ//🇺🇸 //fæt wʌn ˈkænɑːt noʊ//🇬🇧 /["/ˈɪɡnərəns/"]/🇺🇸 /["/ˈɪɡnərəns/"]/
MeaningA saying meaning a big person might be unaware of something.Not knowing something or lacking information.
ExampleThe old saying, 'fat one cannot know,' often comes up in our jokes.The danger of ignorance is that people often fail to recognize their own biases.
RegisterInformalNeutral
How commonBeyond 10,000 (less common)Top 2,000 (common)
CEFR level-C1
Part of speechnoun
Collocationsold saying, humorously suggests, common in jokescomplete, total, utter, betray, demonstrate, display, due to ignorance, in ignorance  (of), in your ignorance
Antonyms-knowledge, awareness, understanding
Common mistakesMisunderstanding the meaning as literally referring to someone's weight., Using it in inappropriate social contexts., Confusing it with similar phrases that imply ignorance.Confused with 'ignore' - Ignorance means lack of knowledge, not simply ignoring something., Using inappropriately in polite contexts - It's often seen as rude to call someone ignorant directly.
Usage notesUsed in casual conversation, often humorously. Avoid in formal settings or serious discussions.Used to refer to a lack of knowledge or awareness. Can be formal in texts but is generally neutral. Not appropriate in polite conversation to describe someone's lack of knowledge directly.

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Fat one cannot know
Ignorance

Frequently asked questions: Fat one cannot know vs Ignorance

What's the difference between Fat one cannot know and Ignorance?

Fat one cannot know: A saying meaning a big person might be unaware of something. Ignorance: Not knowing something or lacking information.

Which is more formal: Fat one cannot know and Ignorance?

Ignorance is the most formal of these.

Which is more common: Fat one cannot know and Ignorance?

Ignorance is the most common in everyday English.

Can you show an example of each?

Fat one cannot know: The old saying, 'fat one cannot know,' often comes up in our jokes. Ignorance: The danger of ignorance is that people often fail to recognize their own biases.

Can I use Fat one cannot know and Ignorance interchangeably?

Not always. Fat one cannot know and Ignorance 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.