I take it "ExPat" is just a w**** British way of saying immigrant?
I take it to mean someone who lives abroad mainly because they feel like it or got sent there, not to seek a whole new life. Someone who isn't completely committed I suppose because they wealthy enough to keep options open. Never thought about it much actually. I don't consider myself an expat or an immigrant because I was born with dual citizenship and spent roughly the same number of years in both places.
https://en.wikipedia.org/wiki/Expatriate
The word expatriate comes from the Latin terms ex ("out of") and patria ("native country, fatherland"). Dictionary definitions for the current meaning of the word include:
Expatriate:
'A person who lives outside their native country' (Oxford),[2] or
'living in a foreign land' (Webster's).[3]
These contrast with definitions of other words with a similar meaning, such as:
Migrant:
'A person who moves from one place to another in order to find work or better living conditions' (Oxford),[4] or
'one that migrates: such as a: a person who moves regularly in order to find work especially in harvesting crops' (Webster's);[5]
or
Immigrant
'A person who comes to live permanently in a foreign country' (Oxford),[6] or
'one that immigrates: such as a: a person who comes to a country to take up permanent residence (Webster's).[7]
The varying use of these terms for different groups of foreigners can thus be seen as implying nuances about wealth, intended length of stay, perceived motives for moving, nationality, and even race. This has caused controversy.