index vs forefinger

index and forefinger both are nouns.

Word	Noun	Adjective	Verb	Adverb
index	Yes	No	Yes	No
forefinger	Yes	No	No	No

As nouns, index and forefinger are synonyms defined as:

Other synonyms of index include index finger.

index (noun)	forefinger (noun)
the finger next to the thumb	the finger next to the thumb
an alphabetical listing of names and topics along with page numbers where they are discussed
a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
a mathematical notation indicating the number of times a quantity is multiplied by itself
a numerical scale used to compare variables with one another or with some reference number