imposture, fraud, sham, fake, humbug, counterfeit mean a thing made to seem other than it is.

imposture applies to any situation in which a spurious object or performance is passed off as genuine.

fraud usually implies a deliberate perversion of the truth.

sham applies to fraudulent imitation of a real thing or action.

fake implies an imitation of or substitution for the genuine but does not necessarily imply dishonesty.

humbug suggests elaborate pretense usually so flagrant as to be transparent.

counterfeit applies especially to the close imitation of something valuable.

assume, affect, pretend, simulate, feign, counterfeit, sham mean to put on a false or deceptive appearance.

assume often implies a justifiable motive rather than an intent to deceive.

affect implies making a false show of possessing, using, or feeling.

pretend implies an overt and sustained false appearance.

simulate suggests a close imitation of the appearance of something.

feign implies more artful invention than pretend, less specific mimicry than simulate.

counterfeit implies achieving the highest degree of verisimilitude of any of these words.

sham implies an obvious falseness that fools only the gullible.