Pahlavi vs Pehlevi

Pahlavi and Pehlevi both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pahlavi	Yes	No	No	No
Pehlevi	Yes	No	No	No

As nouns, Pahlavi and Pehlevi are synonyms defined as:

Pahlavi and Pehlevi: the Iranian language of the Zoroastrian literature of the 3rd to 10th centuries

Other synonyms of Pahlavi include Pahlavi language, Pehlevi language.

Pahlavi (noun)	Pehlevi (noun)
the Iranian language of the Zoroastrian literature of the 3rd to 10th centuries	the Iranian language of the Zoroastrian literature of the 3rd to 10th centuries
the script (derived from the Aramaic alphabet) used to write the Pahlavi language
Shah of Iran who was deposed in 1979 by Islamic fundamentalists (1919-1980)