Synonyms and related words :
able, accepted, acknowledged, admitted, affirmed, agreed, airtight, allowed, approved, arranged, auricular, authenticated, avowed, between us, certified, close, compact, compacted, conceded, confessed, confidential, confirmed, contracted, countersigned, covenanted, dustproof, dusttight, endorsed, engaged, enigmatic, esoteric, fast, firm, gasproof, gastight, granted, hermetic, hermetically sealed, in petto, incalculable, incognizable, inside, lightproof, lighttight, mysterious, not for publication, notarized, off the record, oilproof, oiltight, privileged, professed, promised, puzzling, rainproof, raintight, ratified, received, recognized, settled, shut fast, signed, smokeproof, smoketight, snug, stamped, staunch, stipulated, stormproof, stormtight, strange, sworn and affirmed, sworn to, tight, unapparent, unapprehended, unascertained, unbeknown, uncharted, unclassified, under privilege, undertaken, underwritten, undisclosed, undiscoverable, undiscovered, undivulged, unexplained, unexplored, unexposed, unfamiliar, unfathomed, unheard, unheard-of, unidentified, uninvestigated, unknowable, unknown, unperceived, unplumbed, unpublishable, unrevealed, unsuspected, untouched, validated, virgin, warranted, water-repellant, waterproof, watertight, windproof, windtight