Yes, it can. In is an adverb in the sentence "I will go in" although where the person goes "in" (into) is not defined. With an object noun, in is a preposition, and a phrase could be an adverb or an adjective phrase. E.g. I went in the park. The fountain in the park is broken.
No. The proper adjective Roman is not used as an adverb. There is a VERY rarely-used adverb, Romanly.
The word "as" can be used as an adverb.
Has is a form of the verb "to have" and is not used as an adverb.
An adverb is used to describe verbs, adjectives, or other adverbs.
Adverb
Yes it can be used as an adverb.
No. The adverb would be "scarily."
No, it is not an adverb. Flouncy is an adjective. There is a seldom-used adverb form "flouncily."
Adverbs are used to describe or modify a verb, an adjective, or another adverb.
One adverb (rarely used) is agreeingly.An adverb more frequently used is agreeably, from the related adjective agreeable.
It can be an adverb but is more often an adjective. The adverb is used primarily with the verb "stand."
No, it is not an adverb. The word shady is an adjective. The rarely-used adverb form is shadily.