aversive noun 2adjective 1forms 3 noun2 •An unpleasant stimulus intended to induce a change in behaviour.For general training purposes, opportunities to engage in reproductive acts are not a practical reinforcer, and using aversives that generate fear is fraught with side effects. — 2015 •A grammatical case indicating that something is avoided or feared; the evitative case. adjective1 •Tending to repel; causing avoidance. formsaversives · more aversive · most aversive