No, it can be used as either a noun or a verb.
It is certainly used as such! It is an adjective when it describes something else, such as "his changing personality". It is of course also a noun: "the changing of the seasons".
The adjective form is enigmatic.
fame
indignation
The suffix -ous is added to the noun mountain to form the adjective mountainous.
The proper adjective for Antarctica is Antarctic, as in Antarctic Circle.
Norway is a proper noun, not an adjective. It is the name of a country. It does not change.
The adjective form is enigmatic.
Occasional
indignation
fame
catastrophic
Leisure is already in its adjective form. It does not change between noun and adjective, only between noun/adjective and adverb. "Please complete this at your leisure." = noun "My favorite leisure activity is golf." = adjective "He completed the task leisurely." = adverb
It is Technical
indignation
tendency
Cultural
Korean