little finger vs pinkie

little finger and pinkie both are nouns.

Word	Noun	Adjective	Verb	Adverb
little finger	Yes	No	No	No
pinkie	Yes	No	No	No

As nouns, little finger and pinkie are synonyms defined as:

Other synonyms of little finger include pinky.

little finger (noun)	pinkie (noun)
the finger farthest from the thumb	the finger farthest from the thumb