It is an adjective.
It means apparent or evident .It is used to refer to outward appearance or pretendance.
It is derived from Latin word "ostensus" which means "to show"
Root of the word :
tend/tens/tent means stretch
perceived, professed, seeming, superficial, alleged, supposed,apparent,avowed
ostensibly - adverb
ostensibility - noun
1)The ostensible reason for the increase in crime is poverty but the police chief feels that there could be other reasons too.
2)His cheerfulness is ostensible concealing sadness.
3)The ostensible truth of their theories have to be looked into.
4)His ostensible purpose was charity, but his real goal was popularity.