pre-noun adjectival
what a ...!; how ...!
Pre-noun adjectival used in exclamations to express strong surprise, anger, or admiration. Followed by a noun or noun phrase. Often translated as 'what (a) ...' or 'how ...'.
What luck!
What rude behavior!
what ... is like; the nature of ...
Used in the pattern 〜の何たるか to ask or explain what something truly is, its essence or nature. Often found in formal or philosophical contexts.
I still don't know what love is.
He taught me what friendship is all about.
Kana spelling is common in casual writing and when the kanji is considered unnecessary.
Formed from 何 in the bound reading なん and attributive たる, the classical copular form used before nouns.