1. a state of mental disturbance and disorientation • Syn: mental unsoundness, unbalance • Derivationally related forms: unbalance (for: unbalance), derange • Hypernyms: insanity 2. the act of disturbing the mind or body - his carelessness could have caused an ecological upset - she was unprepared for this sudden overthrow of their normal way of living • Syn: upset, overthrow • Derivationally related forms: derange, upset (for: upset) • Hypernyms: disturbance