Used to emphasize the excessive nature of an action or condition. Calling the police was an undue reaction for such a minor disagreement.
Pro Tip 2/3
Avoid Exaggeration
Do not use 'undue' to describe something mildly excessive; it's meant for bigger issues. Worrying about being a few minutes late shouldn't cause you undue concern.
Pro Tip 3/3
Not Always Negative
'Undue' can describe positive situations where the excess is still improper. His charm earned him undue attention from the judges, despite his mistakes.