
Sydney gave a smarmy grin to her sister before she made the final move to win the game.
The definition of smarmy is someone who comes across as being insincere.
An example of someone who is smarmy is a used car salesman who tries to come across as if he is a distinguished businessman making you a fair deal but who sounds like he is lying.
smarmy

adjective
smarm′i·er, smarm′i·estInformal flattering in an oily, insincere manner; unctuous
Origin of smarmy
from smarm, smalm, to bedaub, smear ( from uncertain or unknown; perhaps ) + -ysmarmy

adjective
smarm·i·er, smarm·i·est- Excessively ingratiating or insincerely earnest. See Synonyms at unctuous.
- Relating to or indulging in lewd conduct; smutty: smarmy jokes.
Origin of smarmy
From smarm to smearRelated Forms:
- smarm·i·ness
noun
smarmy

Adjective
(comparative smarmier, superlative smarmiest)
- Falsely earnest, smug, or ingratiating.
- a smarmy salesman with a big smile
Origin
From smarm, a variant of smalm/smawm.