Archaic noun/adjectival noun. In modern Japanese, this meaning survives almost exclusively in the adverb 正に (まさに).
See also: まさに
「正に」 is a form where the particle に attaches to the continuative form of the old word 正.
certainly; surely; undoubtedly · exactly; precisely; just
famous sword; Masamune blade · sake; Japanese rice wine
dream that comes true
Archaic kanji form; now mostly seen in the fossilized adverb 正に (まさに).
The historical derivation is uncertain; the kanji 正 is conventionally associated with the meaning 'correct' or 'exact'.