極まる・
極まる and 極まりない follow an evaluative word to say that its quality is present to an extreme or unsurpassed degree. Both forms intensify the evaluation; the second is not an ordinary negative.
How the evaluation works
The word before the target supplies the quality being judged, and the target raises that quality to an extreme. Negative judgments are especially common, but the construction itself is not negative: established positive evaluations such as honor and delight are also possible.
Formal and rhetorical evaluations
この対応は不誠実極まりない。
This response is utterly insincere.
Analyze担当者の説明は曖昧極まるものだった。
The representative's explanation was extremely vague.
Analyzeこのような栄誉ある賞をいただき、光栄極まりない。
It is an extraordinary honor to receive such a prestigious award.
AnalyzeThis is a positive, ceremonial use. The context makes the favorable evaluation clear.
Why the second form is not negative
極まる and 極まりない point in the same direction. In the second form, ない contributes the idea that there is no boundary or limit to the quality; it does not cancel the word before it.
Direct extreme evaluation versus the height of a state
The target directly says that a quality is extreme: evaluative word + 極まる or 極まりない. By contrast, noun + の極み forms a noun phrase meaning the height or epitome of that state.
More examples
その発言は無礼極まりない。
That remark is outrageously rude.
Analyze安全を軽視するとは、無責任極まる。
Disregarding safety is utterly irresponsible.
Analyzeこれは危険極まる作業であり、直ちに中止すべきだ。
This is an extremely dangerous operation and should be stopped immediately.
Analyze根拠のない非難は不当極まりない。
Criticism without evidence is utterly unjust.
Analyze式典にお招きいただき、光栄極まりない。
It is the greatest honor to have been invited to the ceremony.
Analyze旧友と心ゆくまで語り合えた一夜は、愉快極まりないものだった。
The evening spent talking to an old friend to our hearts' content was supremely enjoyable.
Analyze