Metanoia is the Greek noun the New Testament uses for repentance, built from meta (after, with a sense of change) and nous (mind). The cognitive register is primary: a change of mind, a reconsideration, a new way of thinking about what you thought before. BDAG opens the entry with "change of mind" and follows with "remorse, repentance" as derived senses. That ordering tells you where the weight sits in the Greek.

The word is not wrong. It is just thinner than the Hebrew it is often translating. When Yochanan the Immerser and Yeshua both call for metanoia, the Aramaic and Hebrew register standing behind the Greek is shuv: turn, return, reverse direction. The Hebrew is a directional word about the whole life. The Greek is a cognitive word about the mind. The two are not opposed, but they are not identical. A change of mind that never becomes a change of direction has run metanoia without running shuv, and the prophets never let Israel settle for the first without the second.

The translation chain matters. The Septuagint uses metanoia to render turn-words in the Hebrew Bible, which carried the Hebrew directional weight into Greek by association. The New Testament inherits that Septuagint register. The word means change of mind in the Greek lexicon, but it arrives in the New Testament carrying Hebrew freight. Collapse the word into its Greek lexicon entry and you get a repentance that happens in the head. Read it through the Hebrew the speakers were thinking in and you get a repentance that moves the feet.