types:
decoy,
steerer
a beguiler who leads someone into danger (usually as part of a plot)
fake,
faker,
fraud,
humbug,
imposter,
impostor,
pretender,
pseud,
pseudo,
role player,
sham,
shammer
a person who makes deceitful pretenses
misleader
someone who leads astray (often deliberately)
sandbagger
someone who deceives you about his true nature or intent in order to take advantage of you
two-timer
someone who deceives a lover or spouse by carrying on a sexual relationship with somebody else
utterer
someone who circulates forged banknotes or counterfeit coins
coiner
a maker of counterfeit coins
Judas
someone who betrays under the guise of friendship
mimic,
mimicker
someone who mimics (especially an actor or actress)
name dropper
someone who pretends that famous people are his/her friends
paperhanger
someone who passes bad checks or counterfeit paper money
quack
an untrained person who pretends to be a physician and who dispenses medical advice
ringer
a contestant entered in a competition under false pretenses
roper
a decoy who lures customers into a gambling establishment (especially one with a fixed game)
shill
a decoy who acts as an enthusiastic customer in order to stimulate the participation of others
Tartufe,
Tartuffe
a hypocrite who pretends to religious piety (after the protagonist in a play by Moliere)
welcher,
welsher
(offensive) someone who swindles you by not repaying a debt or wager