to be far away, to stay at a distance
This is the plain, physical idea behind the word: a person or thing is a long way off, or moves away and keeps its distance. It covers literal space (a person sitting or standing far off, a place too far to reach) and the relational distance that follows when people pull back from someone.
The same picture carries the word's most painful use. When help, justice, or God himself feels far away, the writers of the Psalms reach for this verb. The cry "do not be far from me" is not asking God to move closer in space; it asks him not to stand back when the person praying most needs him to act. The sense of abandonment is built on the simple notion of distance.
The word does not by itself say whether the distance is good or bad. Drawing back can be wise (steering clear of trouble) or tragic (drifting away from God). The context, not the word, supplies the verdict.