Definitions of turn back:
- verb: hold back, as of a danger or an enemy; check the expansion or influence of
Example: "Turn back the tide of communism"
- verb: retrace one's course
Example: "The hikers got into a storm and had to turn back"
- verb: force to go away; used both with concrete and metaphoric meanings
Example: "The supermarket had to turn back many disappointed customers"
- verb: go back to a previous state