cobnut vs hazelnut

cobnut and hazelnut both are nouns.

Word	Noun	Adjective	Verb	Adverb
cobnut	Yes	No	No	No
hazelnut	Yes	No	No	No

As nouns, cobnut and hazelnut are synonyms defined as:

Other synonyms of cobnut include cob, filbert.

As nouns, hazelnut is a hypernym of cobnut; that is, hazelnut is a word with a broader meaning than cobnut:

cobnut: small nut-bearing tree much grown in Europe
hazelnut: any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk

Other hypernyms of cobnut include hazel, hazelnut tree.

cobnut (noun)	hazelnut (noun)
nut of any of several trees of the genus Corylus	nut of any of several trees of the genus Corylus
small nut-bearing tree much grown in Europe	any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk