Shiah Islam vs Shia

Shiah Islam and Shia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Shiah Islam	Yes	No	No	No
Shia	Yes	No	No	No

As nouns, Shiah Islam and Shia are synonyms defined as:

Shiah Islam and Shia: one of the two main branches of orthodox Islam; mainly in Iran

Other synonyms of Shiah Islam include Shiah.

Shiah Islam (noun)	Shia (noun)
one of the two main branches of orthodox Islam; mainly in Iran	one of the two main branches of orthodox Islam; mainly in Iran