built-in vs inbuilt

built-in and inbuilt both are adjectives.

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

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

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

Other synonyms of built-in include constitutional, inherent, integral.

built-in (adjective)	inbuilt (adjective)
existing as an essential constituent or characteristic	existing as an essential constituent or characteristic