to turn aside or depart: move away from a path, a person, or a course of life
The basic image is of leaving a fixed course, stepping off a road, walking away from someone, or abandoning a way of life. What unites these uses is the subject's own movement away from something. Physical and moral departures use the same word, and the Bible exploits that overlap deliberately: stepping off the road and turning away from God are described by the same act.
The moral and relational dimension is the most theologically weighted use in the Hebrew Bible. Israel "turns aside" from the way God commanded (Exodus 32:8, Deuteronomy 9:12); kings are repeatedly evaluated by whether they "did not turn aside" from the sins of Jeroboam (2 Kings 3:3, 10:29, 13:2 and many more). The wisdom tradition inverts this: the wise person "turns aside from evil" (Job 1:1, Proverbs 3:7, 14:16).