Really it depends on who you're talking too. Some people (especially younger people) will just laugh if they're called a yankee or a yank, really I don't think many people would be offended by it, but you never know so it might be best to not go around calling people yankee.
If you ARE trying to insult somebody then this isn't the best term to use as it's only mildly offensive at worst, in this case you should go look up some better insults online, believe me there are tons.
macaroni
The American Revolution
yankee doodle
to make fun of the british
Yankee Doodle
A Yankee doodle is a native or inhabitant of the United States.
I'm a Yankee Doodle Dandy A Yankee Doodle, do or die A real live nephew of my Uncle Sam Born on the Fourth of July I've got a Yankee Doodle sweetheart She's my Yankee Doodle joy Yankee Doodle came to London Just to ride the ponies I am the Yankee Doodle Boy
The duration of Yankee Doodle Pink is 360.0 seconds.
yankee doodle
yankee doodle
The Yankee Doodle Boy was created in 1904.
Yankee doodle put a feather in his hat and called it macaroni Yankee doodle put a "feather in his hat and called it macaroni"!
Yankee Doodle is the state song of Connecticut.
Yankee Doodle is Connecticut's state song.
The duration of Yankee Doodle Dandy is 2.1 hours.
The maccaroni
Yankee Doodle Coffee Shop was created in 1950.