The Greek verb astocheo means to miss the mark, to swerve from, or to deviate from a target. Paul uses it in the Pastoral Epistles to describe those who have abandoned sound doctrine and wandered into empty speculation — the metaphor of an archer whose arrow goes wide of its target.
Paul uses astocheo three times in the Pastorals (1 Timothy 1:6; 6:21; 2 Timothy 2:18). In each case, the deviation is not minor error but a fundamental missing of the Gospel's point. Hymenaeus and Philetus 'missed the mark' regarding the resurrection (2 Timothy 2:18), creating a faith crisis for some. The word implies that truth is knowable and reachable — those who miss it do so through love of controversy, pride, or moral compromise (1 Timothy 6:4-5). The goal of all sound doctrine is love from a pure heart (1 Timothy 1:5) — when that is missed, everything else goes astray.