un·der·state 
(ŭn′dər-stāt)
(ŭn′dər-stāt)tr.v. un·der·stat·ed, un·der·stat·ing, un·der·states
1. To state with less completeness or truth than seems warranted by the facts.
2. To express with restraint or lack of emphasis, especially ironically or for rhetorical effect.
3. To state (a quantity, for example) that is too low: understate corporate financial worth.