Ambiguous vs Hard to know

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

Ambiguous

Top 5,000 (fairly common)B1

Hard to know

Top 2,000 (common)
Most common: Hard to know
 AmbiguousHard to know
Pronunciation🇬🇧 //æmˈbɪɡ.ju.əs//🇺🇸 //æmˈbɪɡ.ju.əs//🇬🇧 //hɑːd tə nəʊ//🇺🇸 //hɑrd tə noʊ//
MeaningSomething that can be understood in different ways.Difficult to understand or determine.
ExampleThe instructions were so ambiguous that no one could follow them.It's hard to know what he really thinks about the situation.
RegisterNeutralNeutral
How commonTop 5,000 (fairly common)Top 2,000 (common)
CEFR levelB1-
Collocationsambiguous statement, ambiguous situation, ambiguous language, ambiguous response, ambiguous meaninghard to know for sure, hard to know exactly, hard to know the truth
Antonymsclear, definite, unambiguous-
Common mistakesUsed as 'ambiguous to' instead of 'ambiguous about', Confused with similar words like 'vague' or 'obscure', Overused in contexts that require more specific languageUsing 'hard to know' instead of 'hard to understand' when discussing comprehension., Confusing it with 'hardly know', which means not knowing much at all., Thinking it can be used in all contexts; it's more casual.
Usage notesUsed in discussions about language or situations where meanings are unclear. Avoid in formal writing when clarity is needed.Use when discussing uncertainty or complexity. It's informal; avoid in formal writing or presentations.

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Hard to know

Frequently asked questions: Ambiguous vs Hard to know

What's the difference between Ambiguous and Hard to know?

Ambiguous: Something that can be understood in different ways. Hard to know: Difficult to understand or determine.

Which is more common: Ambiguous and Hard to know?

Hard to know is the most common in everyday English.

Can you show an example of each?

Ambiguous: The instructions were so ambiguous that no one could follow them. Hard to know: It's hard to know what he really thinks about the situation.

Can I use Ambiguous and Hard to know interchangeably?

Not always. Ambiguous and Hard to know 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.

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