Plea of temporary insanity

At its core, it means although the person pleading temporary insanity is not insane before the act, circumstances rendered him insane at the time he committed the bad act. For example, X comes home and finds Y in bed with her husband, goes "insane" by pulling out a gun and killing Y.

See also: M'Naughten rule

External links:

• The Temporary Insanity Defense in California (http://www.uchastings.edu/plri/spring95/tmpinsan)