up in arms

Etymology
From a now-obsolete sense of.

Adjective

 * 1)  Armed for battle; prepared for or engaged in warfare.
 * 2)  Angry; incensed; preparing for a fight.
 * 1)  Angry; incensed; preparing for a fight.
 * 1)  Angry; incensed; preparing for a fight.

Usage notes

 * "All" may be added as an intensifier at the beginning of the expression, as in: