integral vs built-in

integral is a noun but built-in is not a noun.

Word	Noun	Adjective	Verb	Adverb
integral	Yes	Yes	No	No
built-in	No	Yes	No	No

As adjectives, integral and built-in are synonyms defined as:

integral and built-in: existing as an essential constituent or characteristic

Other synonyms of integral include constitutional, inbuilt, inherent.

integral (noun)	built-in (noun)
the result of a mathematical integration; F(x) is the integral of f(x) if dF/dx = f(x)

integral (adjective)	built-in (adjective)
of or denoted by an integer	existing as an essential constituent or characteristic
existing as an essential constituent or characteristic
constituting the undiminished entirety; lacking nothing essential especially not damaged