sneakingly

As an adverb sneakingly

is in the manner of one who is sneaking or sneaky; slyly, covertly.

As a noun sneak is

one who sneaks; one who moves stealthily to acquire an item or information.

As a verb sneak is

to creep or go stealthily; to come or go while trying to avoid detection, as a person who does not wish to be seen.

As an adjective sneak is

in advance; before release to the general public.

As adverbs the difference between sneakingly and inwardly

is that sneakingly is in the manner of one who is sneaking or sneaky; slyly, covertly while inwardly is in an inward manner; on the inside or to one's self.

As adverbs the difference between speakingly and sneakingly

is that speakingly is (rare) in an expressive manner while sneakingly is in the manner of one who is sneaking or sneaky; slyly, covertly.

As adverbs the difference between sneakingly and snakingly

is that sneakingly is in the manner of one who is sneaking or sneaky; slyly, covertly while snakingly is in a snaking manner; serpentinely.

As adverbs the difference between sneakily and sneakingly

is that sneakily is in a sneaky manner while sneakingly is in the manner of one who is sneaking or sneaky; slyly, covertly.