university student vs college student

university student and college student both are nouns.

Word	Noun	Adjective	Verb	Adverb
university student	Yes	No	No	No
college student	Yes	No	No	No

As nouns, university student and college student are synonyms defined as:

university student and college student: a student enrolled in a college or university

university student (noun)	college student (noun)
a student enrolled in a college or university	a student enrolled in a college or university