Ben Yagoda, UDel Professor of Journalism and English, claims Britishisms in American English (like dodgy, posh, snog) are as common as Americanisms in British English. Here are a few examples from his blog; what do you think, are these expressions Americans commonly use?
Talk to someone in a friendly, informal way; schmooze. Most often used to suggest or imply flattery, as in "butter up," and especially an attempt to flirt with or seduce the chattee
Insolent or audacious in address; coolly impudent or presuming
Senseless, stupid, or foolish
Evasive, tricky, artful; dubious, unreliable
Eager; (with 'on') attracted to
A young man characterized by his enjoyment of social drinking, sport, and other activities considered to be male-oriented, his engagement in casual sexual relationships, and often by attitudes or behaviour regarded as irresponsible, sexist, or boorish