Underground and Unknown

Underground adjective - Undertaken or done so as to escape being observed or known by others.

Unknown and underground are semantically related. In some cases you can use "Unknown" instead the word "Underground" as an adjective or an adverb.

Unknown adjective - Happening or existing without one's knowledge.

Underground and unknown are semantically related. Sometimes you can use "Underground" instead the word "Unknown" as an adjective or an adverb.

Nearby Words: unknowable, unknowing