turn back has 19 distinct synonyms spread across 5 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
retrace one's course
“The hikers got into a storm and had to turn back”
force to go away; used both with concrete and metaphoric meanings
“Drive away potential burglars”
Synonyms, antonyms and the broader and narrower relations for turn back come from Princeton University’s WordNet. Full sources and licences.