Is lighting an adverb or adjective?

Answer 1

Lighting is a noun (a gerund). It is the present participle form of the verb (to light).

It can be used as a noun, or in participial phrases (lighting the way), or as a verb (is lighting, were lighting, will be lighting).

Answer 2

"Lighting" can be both an adverb and an adjective, depending on how it is used in a sentence. As an adverb, it describes how something is being done (e.g., "The room was brightly lit"). As an adjective, it describes a noun by giving more information about its quality (e.g., "The lighting fixtures were modern").