The opposite of somewhere (unspecified location) could be nowhere, or it could be here (opposite of (somewhere else or there), or even there. (a specified location).
Nowhere.
Yes, somewhere is an adverb meaning a definite but indeterminate location. Somewhere can also be a noun.
opposite is an adjective
The opposite of the adverb bitterly is sweetly.The word sweetly is also an adverb.
No. Although often seen with prepositions (e.g. somewhere down the road), it is a noun or an adverb. e.g. It came from somewhere. (noun)/ We went somewhere. (adverb)
Yes, it is an adverb. It simply means "somewhere else."
The adverb "well" is the usual opposite of the adverb "badly." If "badly" is used to mean "extremely or greatly" the opposite could be "slightly." E.g. He was badly bruised./He was slightly bruised.
No, it is an adjective, the opposite of definite. The adverb form is indefinitely.
Roughly
gently
Careful.
The opposite of the adverb firmly (securely) is loosely.*When used to mean forcefully or determinedly (e.g. firmly stated), the opposite could be gently, weakly, or waveringly.
No, it is not an adverb. The word violate is a noun (the opposite word, inviolate, is an adjective , as is violated).