undervalue

verb

1. (transitive)To underestimate, or assign too low a value to (something or someone); to have too little regard for.

   “Near-synonyms: underrate, underappreciate, underween”

   “I write not this with the leaſt intention to undervalue the other parts of Poetry: for Comedy is both excellently inſtructive, and extreamly pleaſant: […]”

   “[…] I undervalu'd all the Enſigns of Authority which belong'd to me, all the Pomp and Splendor of Life which^([sic – meaning with]) which I was ſurrounded.”

noun

1. An undervaluation; a price or rate below the actual worth.

   “[…] he must therefore prove that the contract was not at such an undervalue as would amount to fraud […]”