playfully
No, players is a plural noun. An adverb form of the verb or noun play is playfully.
Yes, it is an adverb, the adverb form of the adjective musical.
No. The word nicer is a comparative form of the adjective nice. The adverb is nicely and the comparative would be "more nicely." (*The term "play nice" is just a colloquial form; play nicely is correct.)
No. Playing is the gerundive form of the verb to play.
The word play can be a noun or a verb. There is the related adjective "playful" which has the adverb form "playfully." The participles of the verb to play (playing and played) can also be used as adjectives, but do not form adverbs.
Heavily is the adverb form of heavy.Heavily
The adverb form is "noisily."
No, it is an adjective. Anonymously is the adverb form.
The related adverb form is decreasingly. It is the adverb form of the present participle, decreasing. The past participle, decreased, does not form an adverb.
The adverb form is academically.
The adverb form is secondarily.
The adverb form is measurably.