Islam vs Wahhabism

Islam and Wahhabism both are nouns.

Word	Noun	Adjective	Verb	Adverb
Islam	Yes	No	No	No
Wahhabism	Yes	No	No	No

As nouns, Wahhabism is a hyponym of Islam; that is, Wahhabism is a word with a more specific, narrower meaning than Islam:

Islam: the monotheistic religious system of Muslims founded in Arabia in the 7th century and based on the teachings of Muhammad as laid down in the Koran
Wahhabism: a conservative and intolerant form of Islam that is practiced in Saudi Arabia

Other hyponyms of Islam include Mahdism, Salafi movement, Salafism, Shiism, Wahabism, Alawism, Ash'arism.

Islam (noun)	Wahhabism (noun)
the monotheistic religious system of Muslims founded in Arabia in the 7th century and based on the teachings of Muhammad as laid down in the Koran	a conservative and intolerant form of Islam that is practiced in Saudi Arabia
the civilization of Muslims collectively which is governed by the Muslim religion