No, it is not (despite the LY ending). The word costly is an adjective (expensive, high-priced).
no prosperous is not an adverb. it is an adjective.
Recession is a noun. It has an adjective form recessional and an adverb recessionally (which refers to the manner). There is a related adverb "recessive" (not dominant) which has the adverb form recessively.
The adverb of benefit is beneficially. The adjective is beneficial and the noun is beneficialness. Benefits is noun and has no adverb.
No, it is not an adverb. Profit can be a noun, or a verb. A related adjective is "profitable" and has the adverb form "profitably."
There are several reasons why a natural, gem-quality diamond is costly, the foremost being it's rarity. Only about 20% of all diamonds mined are gem-quality. Also, lab-created diamonds are less costly that natural diamonds. Industrial quality diamonds are not costly.
Yes it is. It is the adverb form of the adjective expensive, and means in a costly, lavish or extravagant manner.
The superlative for costly is "most costly" or "costliest."
Yes, costly is an adjective. E.g. It was a costly mistake. (One that was expensive to fix, or that led to other bad consequences.)
Costly.
It should be most costly.
1. Adverb Of Time2. Adverb Of Place3. Adverb Of Manner4. Adverb Of Degree of Quantity5. Adverb Of Frequency6. Interrogative Adverb7. Relative Adverb
"Ever" is an adverb.
Softly is an adverb.
The opposite of costly can be cheap, inexpensive, or affordable.
No Silicon is not costly. Pensil is of 3rupees in Pakistan
No, it is not an adverb. Truthful is an adjective, and the adverb form is "truthfully."
An adverb phrase is two or more words that act as an adverb. It would be modified by an adverb or another adverb phrase.