ostensible

Ostantatious is often a misspelling of ostensible.

Ostantatious has no English definition.

As an adjective ostensible is

apparent, evident; meant for open display.

As adjectives the difference between ostensible and obvious

is that ostensible is apparent, evident; meant for open display while obvious is easily discovered, seen, or understood; self-explanatory.

As adjectives the difference between ostensible and plausible

is that ostensible is apparent, evident; meant for open display while plausible is seemingly or apparently valid, likely, or acceptable; credible: a plausible excuse.

As adjectives the difference between flagrant and ostensible

is that flagrant is obvious and offensive, blatant, scandalous or flagrant can be (obsolete) while ostensible is apparent, evident; meant for open display.

As an adjective ostensible

is apparent, evident; meant for open display.

As a noun ostensibility is

the quality of being ostensible.