While the Hebrew word teshuvah appears relatively rarely (primarily as "answer/reply" in contexts like Job 21:34 and 1 Samuel 7:17), its root shuv appears over 1,050 times, making the concept of turning/returning one of the most fundamental in the entire Old Testament. The Prophets' call to "return to the LORD" is the essence of teshuvah — not mere regret, but a complete reorientation of life toward God. This concept becomes "metanoia" (repentance/mind-change) in the New Testament.
Teshuvah means a returning, an answer, or the act of turning back — from the root shuv (to return). In Jewish theology, teshuvah has become the supreme word for repentance: a complete turning back to God. Though the noun is less common, the concept it embodies pervades all of Scripture.