Grammar › N1 · 08 Extremes and impossibility
〜この上ない: the greatest; unsurpassed
N1 · 08 Extremes and impossibility
Means there is nothing higher than this; the best or worst possible.
Used before a noun or at the end: この上ない喜び, この上なく美しい. い-adjective/な-adjective + こと + この上ない is also found. Slightly formal, can be positive or negative. A form with 〜上なく is an adverb.
Examples
この上ない幸せを感じています。
I feel the greatest happiness possible.
あの景色は、この上なく美しかった。
That view was beautiful beyond compare.