Inger vs Ingerman

Inger and Ingerman both are nouns.

Word	Noun	Adjective	Verb	Adverb
Inger	Yes	No	No	No
Ingerman	Yes	No	No	No

As nouns, Inger and Ingerman are synonyms defined as:

Inger and Ingerman: a member of western Finnish people formerly living in the Baltic province where Saint Petersburg was built

Other synonyms of Inger include Ingrian.

Inger (noun)	Ingerman (noun)
a member of western Finnish people formerly living in the Baltic province where Saint Petersburg was built	a member of western Finnish people formerly living in the Baltic province where Saint Petersburg was built