sham (n.)

1670s, "a trick, a hoax, a fraud," also as a verb and an adjective, of uncertain origin; the words burst into use in 1677. Perhaps from sham, a northern dialectal variant of shame (n.); a derivation OED finds "not impossible." Sense of "something meant to be mistaken for something else" is from 1728. The meaning "false front" in pillow-sham (1721) is from the notion of "counterfeit." Related: Shammed; shamming; shammer. Shamateur "amateur sportsman who acts like a professional" is from 1896.

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Definitions of sham from WordNet
sham (v.)
make a pretence of;
Synonyms: simulate / assume / feign
sham (v.)
make believe with the intent to deceive;
He shammed a headache
Synonyms: feign / pretend / affect / dissemble
sham (n.)
something that is a counterfeit; not what it seems to be;
Synonyms: fake / postiche
sham (n.)
a person who makes deceitful pretenses;
Synonyms: imposter / impostor / pretender / fake / faker / fraud / shammer / pseudo / pseud / role player
sham (adj.)
adopted in order to deceive;
sham modesty
Synonyms: assumed / false / fictitious / fictive / pretended / put on