ostensibility vs semblance

ostensibility and semblance both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostensibility	Yes	No	No	No
semblance	Yes	No	No	No

As nouns, semblance is a hypernym of ostensibility; that is, semblance is a word with a broader meaning than ostensibility:

ostensibility: The quality of being professed, supposed rather than demonstrably true or real.
semblance: an outward or token appearance or form that is deliberately misleading

Other hypernyms of ostensibility include color, colour, gloss.

ostensibility (noun)	semblance (noun)
The quality of being professed, supposed rather than demonstrably true or real.	picture consisting of a graphic image of a person or thing
	an outward or token appearance or form that is deliberately misleading
	an erroneous mental representation