かねない says something bad could well happen: "could", "might end up". It goes after the ます-stem of a verb, and the result it warns about is always unwelcome.
、。
If we leave it like this, it could turn into something serious.
。
What he said could easily be misunderstood.
、。
If you look at your phone while driving, you could cause an accident.
- × 事故を起こすかねない → 事故を起こしかねない
かねない or かもしれない
says something is possible, good or bad. かねない warns: the bad outcome is a real risk. A good outcome takes かもしれない.
、。
If you push yourself too hard, you could ruin your health.
、。
If you work hard, you might pass.
- × 頑張れば、合格しかねない → 頑張れば、合格するかもしれない
かねない and かねる
means "can't", and its polite form is a refusal:
, "I'm afraid I can't accept". かねない is its negative form, and it means "may well happen".
、。
I'm sorry, but I'm unable to answer that question.
、。
At this rate, there could be an accident.
Usage notes
These go beyond warning about a situation.
About a person
With a person as the subject, かねない says they are the kind who would do something bad: "he's capable of it".
、。
He's just the type to actually do it.
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かねない belongs to writing, the news and serious talk at work. Among friends, かもしれない or does the same job.
、、。
If you say that, she might get angry.
Lingaku