1.Definition: beyond normal limits
"His dress stops just short of undue elegance"
2.Definition: lacking justification or authorization
"Desire for undue private profit"
3.Definition: not appropriate or proper (or even legal) in the circumstances
"Undue influence", "I didn't want to show undue excitement", "Accused of using undue force"
4.Definition: not yet payable
"An undue loan"