unknown

Undercover is a related term of unknown.

As adjectives the difference between undercover and unknown

is that undercover is performed or happening in secret while unknown is not known; unidentified; not well known.

As nouns the difference between undercover and unknown

is that undercover is a person who works while unknown is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

Unknown is a related term of difficult.

As adjectives the difference between unknown and difficult

is that unknown is not known; unidentified; not well known while difficult is hard, not easy, requiring much effort.

As a noun unknown

is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

As a verb difficult is

(obsolete|transitive) to make difficult; to impede; to perplex.

Surreptitious is a related term of unknown.

As adjectives the difference between surreptitious and unknown

is that surreptitious is stealth]]y, furtive, [[hidden|well hidden, covert (especially movements) while unknown is not known; unidentified; not well known.

As a noun unknown is

(algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

Unknown is a related term of puzzling.

As adjectives the difference between unknown and puzzling

is that unknown is not known; unidentified; not well known while puzzling is difficult to understand or explain; enigmatic or confusing; perplexing.

As nouns the difference between unknown and puzzling

is that unknown is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found while puzzling is time spent pondering something confusing.

As a verb puzzling is

.

Unknown is a related term of perplexing.

As adjectives the difference between unknown and perplexing

is that unknown is not known; unidentified; not well known while perplexing is confusing or puzzling.

As a noun unknown

is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

As a verb perplexing is

.

Mysterious is a synonym of unknown.

As adjectives the difference between mysterious and unknown

is that mysterious is of unknown origin while unknown is not known; unidentified; not well known.

As a noun unknown is

(algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

Unknown is a related term of doubtful.

As adjectives the difference between unknown and doubtful

is that unknown is not known; unidentified; not well known while doubtful is subject to, or causing doubt.

As a noun unknown

is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

Covert is a related term of unknown.

As adjectives the difference between covert and unknown

is that covert is hidden, covered over; overgrown, sheltered while unknown is not known; unidentified; not well known.

As nouns the difference between covert and unknown

is that covert is area of thick undergrowth where animals hide while unknown is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

Unknown is a related term of veiled.

As adjectives the difference between unknown and veiled

is that unknown is not known; unidentified; not well known while veiled is hidden, such as by a veil.

As a noun unknown

is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.

As a verb veiled is

(veil).

Unknown is a related term of undecipherable.

As adjectives the difference between unknown and undecipherable

is that unknown is not known; unidentified; not well known while undecipherable is not easily deciphered; difficult to read.

As a noun unknown

is (algebra) a variable (usually x'', ''y'' or ''z ) whose value is to be found.