Both 本【ほん】性【しょう】 and 正【しょう】体【たい】 share the same primary definition of "true character" on jisho.org. The secondary definitions appear to be somewhat synonymous, though both words don't have the exact same definition through and through.

Additionally, I learned about both words in context sentences for the verb 現【あらわ】す, and the meanings to appear to be similar:

  • 正体を現す: to reveal one's true nature
  • 本性を現す: show one's true colors

Can they be used somewhat interchangeably, or are there specific contexts in which one would make more sense, or be more appropriate than the other?

2 Answers 2


To some extent, they are interchangeable. The main difference is that 正体 is more about physical appearance but 本性 is always inner personality.

Practically, most instances of 本性を現す falls into the following usage:

  • その男は本性を現した

meaning 'a guy (who appeared to be kind/friendly/good) turned out to be a bad guy' (of course, the subject can be anything). For this usage, using 正体 is possible, but it sounds like figurative (the guy was a villain in the disguise of a good guy).

On the other hand, typically in manga or games, some enemies or monsters transform themselves in the way that their external appearances change completely (disclaimer: I don't know recent games, but at least it used to be the case). In such cases,

  • モンスターが正体を現した

is much more normal. 本性 may be used, but I suppose it is technically wrong (assuming the monster is a bad one).

Also, as suggested above, 本性 is usually something bad. 正体 doesn't have to be so.

For example, consider a situation where someone hides their identity and then reveals it later:

  • 正体を明かした

Here 本性 is impossible. Yet another example, Audrey Hepburn in Roman Holiday as a princess is her 正体 and not 本性.


  • 彼の正体を見破った

means to find out what he really is (a movie star, a prince, etc.)

  • 彼の本性を見破った

means to find out his true intent/what kind of person he is.


本性 (ほんしょう) emphasizes inherent qualities, suitable when highlighting someone's deep-seated nature, e.g., "彼の本性が明らかになった" (His true nature became clear).

正体 (しょうたい) focuses on unveiling hidden truths or identities, used when revealing concealed realities, e.g., "犯人の正体が明らかになった" (The criminal's true identity was revealed).

While interchangeable in some contexts, 本性 is about innate character, and 正体 about revealing hidden truths or identities.

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