"Staying" is the present participle or gerund form of the verb "stay". In a sentence, the participle usually functions as an adjective and the gerund as a noun, but the participle can also function as a verb as part of a progressive tense.
adverb
what part of speech is beneath
i want to know what part of speech is camping
The part of speech is a adjective
Oppose is a verb.
"Staying" is a present participle, which is a form of a verb that can function as an adjective or adverb.
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.
The part of speech for "breezy" is an adjective.
The part of speech for "buried" is a verb.
The part of speech for "indefinite" is an adjective.