本人
ほんにん · honnin · JLPT N3 · noun
the person himself
🧍 本人 = origin, true (本) + person (人): the very person in question
本 means root or origin, so 本人 is the original person: the actual one being talked about, not someone acting for them. Forms often ask you to confirm you are 本人, meaning you are the person yourself.
本 — tree 木 + mark at base
本 is a pictograph of a tree (木) with a stroke at its base, marking the roots. From this 'root' meaning it extended to 'origin,' 'source,' and 'foundation.' In modern usage it also serves as a measure word for bound objects like books.
人 — pictograph of a standing person
人 is a pictograph showing a person viewed from the side, with two strokes representing the legs and torso of a standing human. In oracle bone script it clearly depicted a figure leaning slightly forward. The meaning has remained 'person' or 'human' throughout its history.