To turn away, turn aside, or deviate. Used in the Pastoral Letters of people who have turned away from sound teaching to pursue myths, and as a command to 'avoid' foolish controversies. Also used medically of a dislocated limb (Hebrews 12:13).
Ektrepō in the Pastoral Epistles describes one of the characteristic dangers of false teaching: the gradual turning aside from truth. In 1 Timothy 1:6, those who 'have turned to meaningless talk' have wandered from the goal of love from a pure heart. In 2 Timothy 4:4, people 'turn their ears away' from truth to myths. Apostasy rarely happens in one dramatic leap but in a series of small turnings. The Hebrews use is equally instructive: a dislocated limb must be straightened so it does not become permanently lame.