ninja-like
The word silently *is* an adverb. The adjective form is "silent."
Silently is an adverb. Many adverbs end in the prefix -LY.
Noisily
It is neither. The word silently is an adverb, the adverb form of the adjective silent.
Yes, it is the adverb form of the adjective silent.
To mime is to act out silently.
Retreat, abort
The word silently *is* an adverb. The adjective form is "silent."
The word is silentium.
silently
more silently
Silently is an adverb. Many adverbs end in the prefix -LY.
To directly answer your question: quickly slowly quietly always
creeps
cheeky
Noisily
It is neither. The word silently is an adverb, the adverb form of the adjective silent.