Not due; not yet owing; as, an undue debt, note, or bond. [1913 Webster]
Not right; not lawful or legal; improper; as, an undue proceeding. Bacon. [1913 Webster]
Not agreeable to a rule or standard, or to duty; disproportioned; excessive; immoderate; inordinate; as, an undue attachment to forms; an undue rigor in the execution of law. [1913 Webster]

Undue influence (Law), any improper or wrongful constraint, machination, or urgency of persuasion, by which one's will is overcome and he is induced to do or forbear an act which he would not do, or would do, if left to act freely. Abbott.

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OXFORD DICTIONARY

undue, adj.
1 excessive, disproportionate.
2 not suitable.
3 not owed.

Idiom

undue influence Law influence by which a person is induced to act otherwise than by his or her own free will, or without adequate attention to the consequences.

Derivative

unduly adv.

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THESAURUS

undue

a bit much, abandoned, aberrant, abnormal, abominable, atrocious, boundless, criminal, cutthroat, delinquent, deviant, disgraceful, dizzy, egregious, enormous, evil, exacting, exaggerated, excessive, exorbitant, extortionate, extravagant, extreme, fabulous, fancy, gigantic, gluttonous, gouging, grossly overpriced, hardly the thing, high, hyperbolic, hypertrophied, ignominious, ill-timed, illegal, immoderate, improper, inappropriate, inapt, incontinent, incorrect, indecorous, inept, inequitable, infamous, inflationary, iniquitous, inordinate, intemperate, monstrous, nonmeritorious, not coming, not done, not outstanding, not the thing, off-base, off-color, out of bounds, out of sight, out-of-line, outrageous, overbig, overdeveloped, overgreat, overgrown, overlarge, overmuch, overpriced, overweening, preposterous, prohibitive, sacrilegious, scandalous, shameful, shameless, sinful, skyrocketing, spiraling, steep, stiff, terrible, too much, towering, unapt, unbalanced, unbridled, unconscionable, undeserved, undeserving, unearned, unentitled, unequal, unequitable, uneven, unfit, unfitting, unjust, unjustifiable, unjustified, unlawful, unmeasurable, unmeet, unmerited, unmeriting, unowed, unowing, unreasonable, unrestrained, unrighteous, unrightful, unseasonable, unseemly, unsuitable, untimely, unwarrantable, unwarranted, unworthy, usurious, wicked, wrong, wrongful

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ROGET THESAURUS

undue

Undueness

N undueness, malum prohibitum, impropriety, illegality, falseness, emptiness of title, invalidity of title, illegitimacy, loss of right, disfranchisement, forfeiture, usurpation, tort, violation, breach, encroachment, presumption, assumption, seizure, stretch, exaction, imposition, lion's share, usurper, pretender, undue, unlawful, unconstitutional, illicit, unauthorized, unwarranted, disallowed, unallowed, unsanctioned, unjustified, unentitled, disentitled, unqualified, disqualified, unprivileged, unchartered, illegitimate, bastard, spurious, supposititious, false, usurped, tortious, undeserved, unmerited, unearned, unfulfilled, forfeited, disfranchised, improper, unmeet, unfit, unbefitting, unseemly, unbecoming, misbecoming, seemless, contra bonos mores, not the thing, out of the question, not to be thought of, preposterous, pretentious, would-be, filius nullius.

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