わけがない · i-adjective
| Form | Positive | Negative |
|---|---|---|
| Dictionary | わけがない | わけがなくない |
| Polite | わけがないです | わけがなくないですalso わけがなくありません |
| Past polite | わけがなかったです | わけがなくなかったですalso わけがなくありませんでした |
| Past | わけがなかった | わけがなくなかった |
| Te-form | わけがなくて | わけがなくなくて |
| Adverbial | わけがなく | |
| Conditional | わけがなければ | わけがなくなければ |
| Tara conditional | わけがなかったら | わけがなくなかったら |
there is no way that ...; it is impossible that ...; cannot possibly ...
A strong negative judgment by the speaker that something is impossible, unreasonable, or cannot be true. Commonly follows a plain-form verb, adjective, or noun phrase.
Adjectival use meaning that something presents no difficulty. This can be confused with the much more frequent grammar pattern 'there is no way that ...', so context such as 彼には or そのくらいなら is important.
There is no way a child could carry such heavy luggage alone.
He could not possibly forget a promise like that.
Mental arithmetic at that level is easy for him.
Once you get used to it, this task is no trouble.
はずがない also denies that something can be true, but it leans on logical expectation or evidence, while 訳がない sounds more forceful and dismissive.
ありえない is a standalone adjective/exclamation meaning 'impossible' or 'unbelievable', while 訳がない is a sentence-ending pattern that follows a clause to assert impossibility.
ということはない softly denies a specific claim or hypothetical, while わけがない is a stronger, more logical assertion that something is impossible.
わけない is a shorter adjectival form meaning 'easy, no trouble', which learners often confuse with the visually similar 訳がない that instead means 'there's no way that...'.
わけがない makes a strong claim that something is impossible ('there's no way that...'), whereas 訳じゃない just denies one particular interpretation without saying it's impossible.
わけではない softly denies one interpretation ('it doesn't mean that...'), while わけがない strongly denies any possibility ('there's no way that...').
Kanji spelling given; 訳 here means something like 'reason' or 'circumstances'. Kana is still generally preferred in learner-facing and everyday writing.
Mixed kana-kanji spelling given. It is understandable, but the all-kana form is usually simpler and more common.
Fully kanji-based spelling given. It may look more formal or heavier than the usual kana spelling.
From 訳 meaning 'reason, circumstances' plus the subject marker が and ない 'not exist'. The core idea is literally 'there is no reason/way'; the 'easy' sense can be understood as 'there is no difficulty or complication.'