THESAURUS
Conceal
becloud, befog, blanket, blind, bosom, bury, cache, camouflage, classify, cloak, cloud, cover, cover up, curtain, disguise, dissemble, distract attention from, ditch, eclipse, ensconce, enshroud, envelop, file and forget, gloss over, hide, hold out on, in petto, keep, keep back, keep between us, keep buttoned up, keep close, keep dark, keep from, keep hidden, keep in ignorance, keep mum, keep secret, keep snug, keep under cover, keep under wraps, make no sign, mask, never let on, not give away, not tell, obfuscate, obscure, occult, play dumb, screen, secrete, shade, shroud, slur over, stash, varnish, veil, whitewash, withhold
ROGET THESAURUS
Conceal
Covering
VB
cover, superpose, superimpose, overlay, overspread, wrap, encase, incase, face, case, veneer, pave, paper, tip, cap, bind, bulkhead, bulkhead in, clapboard, coat, paint, varnish, pay, incrust, stucco, dab, plaster, tar, wash, besmear, bedaub, anoint, do over, gild, plate, japan, lacquer, lacker, enamel, whitewash, parget, lay it on thick, overlie, overarch, endome, conceal, anodize, galvanize.
Invisibility
VB
be invisible, be hidden, lurk, escape notice, render invisible, conceal, put out of sight, not see, lose sight of.
Unintelligibility
VB
be unintelligible, require explanation, have a doubtful meaning, pass comprehension, render unintelligible, conceal, darken, confuse, perplex, not understand, lose, lose the clue, miss, not know what to make of, be able to make nothing of, give it up, not be able to account for, not be able to make either head or tail of, be at sea, wonder, see through a glass darkly, not understand one another, play at cross purposes.
Concealment
VB
conceal, hide, secrete, put out of sight, lock up, seal up, bottle up, encrypt, encode, cipher, cover, screen, cloak, veil, shroud, cover up one's tracks, screen from sight, screen from observation, drawing the veil, draw the curtain, close the curtain, curtain, shade, eclipse, throw a view over, be cloud, be mask, mask, disguise, ensconce, muffle, smother, befog, whisper, keep from, keep back, keep to oneself, keep snug, keep close, keep secret, keep dark, bury, sink, suppress, keep from, keep from out of view, keep from out of sight, keep in the shade, throw into the shade, throw into background, stifle, hush up, smother, withhold, reserve, fence with a question, ignore, keep a secret, keep one's own counsel, hold one's tongue, make no sign, not let it go further, not breathe a word, not breathe a syllable about, not let the right hand know what the left is doing, hide one's light under a bushel, bury one's talent in a napkin, keep in the dark, leave in the dark, keep in the ignorance, blind, blind the eyes, blindfold, hoodwink, mystify, puzzle, bamboozle, be concealed, suffer an eclipse, retire from sight, couch, hide oneself, lie hid, lie in perdu, lie in close, lie in ambush (ambush), seclude oneself, lurk, sneak, skulk, slink, prowl, steal into, steal out of, steal by, steal along, play at bopeep, play at hide and seek, hide in holes and corners, still hunt.