arcane

As a noun alchemy

is the ancient search for a universal panacea, and of the philosopher's stone, that eventually developed into chemistry.

As an adjective arcane is

understood by only a few; obscure; requiring secret or mysterious knowledge.

As adjectives the difference between turgid and arcane

is that turgid is distended beyond the natural state by some internal agent, especially fluid, or expansive force while arcane is understood by only a few; obscure; requiring secret or mysterious knowledge.

As adjectives the difference between arcane and null

is that arcane is understood by only a few; obscure; requiring secret or mysterious knowledge while null is having no validity, "null and void.

As a noun null is

a non-existent or empty value or set of values.

As a verb null is

to nullify; to annul.

As adjectives the difference between erudite and arcane

is that erudite is while arcane is understood by only a few; obscure; requiring secret or mysterious knowledge.

As adjectives the difference between illusory and arcane

is that illusory is resulting from an illusion; deceptive, imaginary, unreal while arcane is understood by only a few; obscure; requiring secret or mysterious knowledge.

As an adjective arcane

is understood by only a few; obscure; requiring secret or mysterious knowledge.

As an adverb inscrutably is

in an inscrutable manner.

As a noun mysticism

is the beliefs, ideas, or thoughts of mystics.

As an adjective arcane is

understood by only a few; obscure; requiring secret or mysterious knowledge.

As adjectives the difference between arcane and prosaic

is that arcane is understood by only a few; obscure; requiring secret or mysterious knowledge while prosaic is pertaining to or having the characteristics of prose.

As adjectives the difference between obtuse and arcane

is that obtuse is blunt; not sharp while arcane is understood by only a few; obscure; requiring secret or mysterious knowledge.

As adjectives the difference between arcane and unknown

is that arcane is understood by only a few; obscure; requiring secret or mysterious knowledge 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.