Archaic or highly literary word meaning 'real' or 'true'. In modern Japanese, it is rarely used outside of classical contexts or fixed expressions. The adverbial use is particularly old-fashioned.
This is a true treasure.
It was a truly beautiful scenery.
Rare kanji spelling; the word is almost always written in kana in modern Japanese.
Variant kanji spelling, equally rare.
A Chinese-derived word from 真個 “truly; genuine,” with 箇 used as a variant of 個.