interscholastic vs interschool

interscholastic and interschool both are adjectives.

Word	Noun	Adjective	Verb	Adverb
interscholastic	No	Yes	No	No
interschool	No	Yes	No	No

As adjectives, interscholastic and interschool are synonyms defined as:

interscholastic and interschool: used of competition or cooperation between secondary schools

interscholastic (adjective)	interschool (adjective)
used of competition or cooperation between secondary schools	used of competition or cooperation between secondary schools