wage hike vs salary increase

wage hike and salary increase both are nouns.

Word	Noun	Adjective	Verb	Adverb
wage hike	Yes	No	No	No
salary increase	Yes	No	No	No

As nouns, wage hike and salary increase are synonyms defined as:

Other synonyms of wage hike include hike, raise, rise, wage increase.

wage hike (noun)	salary increase (noun)
the amount a salary is increased	the amount a salary is increased