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"
lacking justification or authorization
"desire for undue private profit"
"unwarranted limitations of personal freedom"
beyond normal limits
"excessive charges"
"a book of inordinate length"
"his dress stops just short of undue elegance"
"unreasonable demands"
Excessive; going beyond that what is natural or sufficient.
"The committee decided to reject his proposal because it relied on undue optimism about future market trends."