It depends on what it is modifying, a noun or a verb. It is usually an adjective.
Nearest is just the superlative form of the adjective near. But like some other adjectives, the comparative forms can also function as the comparatives for the adverb (nearly).
e.g.
The nearest star (adjective)
The new houses were built nearest the cliff (most nearly, adverb)
Yes, it can be a preposition, when used with an object (e.g. nearest the town). The preposition phrase, or just the word nearest, can be an adjective or an adverb.
Dark can be an adjective or a noun. Darkly is an adverb.
Adverb.Here is an adverb, not an adjective.
its an adverb an adjective is a descriptive word an adverb is a feeling
An adverb describes a verb, an adjective or another adverb.
It can be an adjective OR an adverb. adjective -- You dog is a friendly dog adverb -- She always talks friendly to me
"Shyly" is an adverb. It is used to describe how someone is behaving in a timid or bashful manner.
Nervous is an adjective. The adverb form is nervously.
Yes, "especially" can function as both an adverb and an adjective. As an adverb, it modifies a verb, an adjective, another adverb, or a sentence. As an adjective, it describes a noun.
'The' is neither an adjective nor an adverb. It is an article.
No, it is not. It is an adverb, the adverb form of the adjective unsteady.
No, it is an adverb. It is the adverb form of the adjective perfect.