next-to-last vs third-year

next-to-last and third-year both are adjectives.

Word	Noun	Adjective	Verb	Adverb
next-to-last	No	Yes	No	No
third-year	No	Yes	No	No

As adjectives, next-to-last and third-year are synonyms defined as:

next-to-last and third-year: used of the third or next to final year in United States high school or college

Other synonyms of next-to-last include junior.

next-to-last (adjective)	third-year (adjective)
used of the third or next to final year in United States high school or college	used of the third or next to final year in United States high school or college
second last