surreptitious

As a noun mystery

is something secret or unexplainable; an unknown.

As an adjective surreptitious is

stealth]]y, furtive, [[hidden|well hidden, covert (especially movements).

As adjectives the difference between surreptitious and reticent

is that surreptitious is stealth]]y, furtive, [[hidden|well hidden, covert (especially movements) while reticent is reluctant; reticent.

As adjectives the difference between immutable and surreptitious

is that immutable is unable to be changed without exception while surreptitious is stealth]]y, furtive, [[hidden|well hidden, covert (especially movements).

As a noun immutable

is something that cannot be changed.

As an acronym cow

is (computing).

As an adjective surreptitious is

stealth]]y, furtive, [[hidden|well hidden, covert (especially movements).

As an adverb furtively

is in a furtive manner.

As an adjective surreptitious is

stealth]]y, furtive, [[hidden|well hidden, covert (especially movements).

As adjectives the difference between conspicuous and surreptitious

is that conspicuous is obvious or easy to notice while surreptitious is stealth]]y, furtive, [[hidden|well hidden, covert (especially movements).

As adjectives the difference between fraudulent and surreptitious

is that fraudulent is dishonest; based on fraud or deception while surreptitious is stealth]]y, furtive, [[hidden|well hidden, covert (especially movements).

As adjectives the difference between sneak and surreptitious

is that sneak is in advance; before release to the general public while surreptitious is stealthy, furtive, well hidden, covert (especially movements).

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 adjectives the difference between surreptitious and obvious

is that surreptitious is stealthy, furtive, well hidden, covert (especially movements) while obvious is easily discovered, seen, or understood; self-explanatory.

As adjectives the difference between surreptitious and suspicious

is that surreptitious is stealth]]y, furtive, [[hidden|well hidden, covert (especially movements) while suspicious is arousing suspicion.