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to be wise or sensible enough to avoid doing something foolish or wrong
She knows better than to spend all her money on clothes.
She is wise enough not to waste her money on clothes.
He should know better than to drive after drinking.
He ought to be sensible enough to avoid driving while intoxicated.
Commonly used to express that someone should have the common sense or experience to avoid a mistake.
Use 'know better' to imply wisdom or experience, not just knowledge. For example, 'She knows better than to skip meals' means she understands the consequences, not just that she is aware of them.
This phrase often carries a slightly critical or parental tone. Use it when advising someone who should already know better, not for general advice.
The phrase combines the verb 'know' (Old English 'cnawan') with the comparative adjective 'better' (Old English 'betera'). The idiomatic use of 'know better' emerged in the early 19th century to imply wisdom or experience beyond naive actions.
This phrase is often used in advice or criticism, implying that the person being addressed has enough experience or intelligence to avoid a particular mistake. It can sound critical, so tone and context matter.