Maybe it depends on where you are. Growing up in New England, I heard it used in reference to Europeans and especially immigrants from certain European nations. I never thought it meant any particular group. It was about how new they were, not where they came from.

It always sounded derisive to me, but relatively mildly so—not usually contemptuous or hateful. As I recall, it was often humorously meant and tended to be used by people who were themselves less recent immigrants or maybe second generation. I haven’t heard it in a long time.

Any immigrant who just arrived. More appropriate for those who actually came by boat. Growing up it was mostly about Europeans coming over, like my grandfather came over on a ship.

In Miami we would say fresh of the raft. Mexicans walk across the border so the term isn’t usually used for them. In Florida we used to say the Venezuelans fly in as opposed to Cubans who float in.

It’s all kind of derogatory I guess. I wouldn’t use it unless I know I’m with people who either understand it’s said tongue and cheek or who know I think nothing negative about new immigrants. I’m just the opposite really, my life is full of people who immigrated to America, to me that is America.

Any immigrate

@Jeruba I live in California. I was always used to that term being a general reference about immigrants (Europeans, Asians, or otherwise) and how people try to assimilate in a new culture. The inspiration of the term even makes sense based on the early history of how (especially European) immigrants begin to first arrive on boats and ships in America.
However, I do also found it interesting to learn how that term can largely resonate with the Asian-American community based on their own endurance too. I know “FOB” doesn’t usually carry a lot of positive connotations either and can be a facetious term at times among former immigrants and close friends.

@JLeslie I find it interesting how the term can also have several variations based on locality.

No. In the 1900–1920 time frame, it referred to immigrant Irish, Italian, Jewish, and all sorts of other European immigrants.

The key word may be “fresh”

I’ve always thought it described any immigrant that arrived by ship.
That would be three of my grandparents. .