Well in Blighty, they would be called
• adjective (jammier, jammiest)
Brit. Informal lucky, flukey
eg: That jammy sod won the lottery again
Jammy is a word I use on a fairly regular basis without really knowing why or where it comes from. It may derive from the 19th century terms "jam-up", "bang-up", "slap-up" meaning "first-rate". Whether it refers to actual jam (or jelly in the US) is a matter of debate.
There is also a phrase ”he has his bread (or cake) with jam on” which again basically means he’s a lucky b*stard.
Other forms include:
Usage would be:
The jammy beggar just got a promotion and he’s only been here three weeks
No-one ever notices that jammy bastard leaving early etc
If you’re using jammy to describe someone, it’s fairly certain that you’re suffering from sour grapes … so don’t use it to congratulate a friend on their good fortune!
NB: Do not confuse with the Rap definition of jammy … which is a euphemism for the male member!