Webster’s Revised Unabridged Dictionary · 1913
Ostensibly
Os·ten′si·bly (ŏs·tĕn′sĭ·bly̆), adv. In an ostensible manner; avowedly; professedly; apparently. Walsh.
Ostensibly, we were intended to prevent filibustering into Texas, but really as a menace to Mexico. U. S. Grant.