Undervalue, v. t.
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.
1 other Webster entry under this spelling
Undervalue, n.
A low rate or price; a price less than the real worth; undervaluation. Milton.
Shades of meaning
Fernald has no entry of its own for undervalue; he lists it under disparage.
Where he writes about it:
A witness or a statement is discredited; the currency is depreciated; a good name is dishonored by unworthy conduct; we underestimate in our own minds; we may underrate or undervalue in statement to others. — from disparage