high-level vs high-altitude

high-level and high-altitude both are adjectives.

Word	Noun	Adjective	Verb	Adverb
high-level	No	Yes	No	No
high-altitude	No	Yes	No	No

As adjectives, high-level and high-altitude are synonyms defined as:

high-level and high-altitude: occurring at or from a relative high altitude

high-level (adjective)	high-altitude (adjective)
occurring at or from a relative high altitude	occurring at or from a relative high altitude
at an elevated level in rank or importance