dis·al·low 
(dĭs′ə-lou)
(dĭs′ə-lou)tr.v. dis·al·lowed, dis·al·low·ing, dis·al·lows
1. To refuse to allow: "[The government] disallowed his aging and dying parents any reunion with their only child" (John Simon).
2. To reject as invalid, untrue, or improper.
[Middle English disallowen, from Old French desalouer, to reprimand : des-, dis- + alouer, to approve; see ALLOW.]
dis′al·lowa·ble adj.
dis′al·lowance n.