Webster's Revised Unabridged Dictionary · 1913

Undervalue

Undervalue , transitive verb

1.
To value, rate, or estimate below the real worth; to depreciate.
2.
To esteem lightly; to treat as of little worth; to hold in mean estimation; to despise.
In comparison of it I undervalued all ensigns of authority. — Atterbury
I write not this with the least intention to undervalue the other parts of poetry. — Dryden

Undervalue , noun

A low rate or price; a price less than the real worth; undervaluation. — Milton