to shrink back physically or emotionally, e.g. in horror, fear, or disgust
said of a firearm: to move backwards sharply when fired
to spring back or into an uncompressed position; to rebound
The spring recoiled
(+ on/upon) to return with an adverse effect to a source or starting point
Their hatred recoiled on themselves
[Middle English reculen from Old French reculer move backwards, from re- + Latin culus buttocks]