What is the difference between Expat and Migrant?

Racist superiority complex.

I’ve seen a lot of discourse saying that the difference between “expat” and “immigrant” is that expats are usually white, wealthy, and from the West, but having lived a couple of years in Bangladesh, there they refer to Bangladeshis living in the Gulf countries as laborers as “expats,” so I don’t think the argument actually holds up.

Expats have more money.

An “expat” is specifically someone who lives outside their native country. It often refers to a skilled worker or retiree from a wealthy country, but this isn’t always the case. A “migrant” is someone who leaves where they normally live for some reason (especially work) but does not necessarily leave permanently or even cross borders. There are, for instance, many “migrant” workers in the US who are citizens—they just move throughout the country to go wherever there’s a great deal of agricultural work at a given time.

Also if you look below the answers to your question here you'll see several more threads where people have asked exactly the same question before.

ESL here I worked for a financial institution, and foreign employees who were paid (a lot of money) to live overseas were called "expats". Migrants often walk and swim to enter another country.

Expat includes “Remittance man” a somewhat obsolete term for a younger son of a wealthy family (usually British) who traveled the world on family money. If he settled down he was both an expat and a remittance man. The US West had a fair number of remittance men in the cowboy period and the gold rush. And in “American Western” movies. The spaghetti westerns sometimes had them, same for the tv series set in the west of that period.

Traditionally, an expat is someone working abroad who intends to return home. An emigrant has completely relocated. If a British person goes to Saudi Arabia on a one-year contract, or goes to his British employer's Frankfurt office for a few months, he's an expat. If he goes to Australia or Canada to live there on the assumption it's better than staying in the UK, he has emigrated. In recent years this has been complicated by a straw-man argument where left-wing people claim right-wing people think the distinction is skin colour (the right wing people don't actually do this) and therefore the right-wing people are evil. This causes a lot of confusion. It ignores the large number of south and southeast Asian expats in the Gulf states, and the large number of British emigrants... everywhere they can emigrate to. So: the older and/or right-wing meaning is that an expat is temporarily abroad. The new and/or left-wing meaning is that an expat is a white Anglo-Saxon type.

Skin color.

Expats move temporarily for a mostly determined period of time (e.g school, temporary contract job, etc.), whereas migrants move with the intention of staying permanently

Per the OED: expat (expatriate) - An expatriated person. In modern usage, a person who lives in a foreign country. migrant - A person who moves temporarily or seasonally from place to place; a person on a journey immigrant - A person who comes to settle permanently in another country or region ex-patriot is not officially a word, though of course, patriot is: patriot - A person who loves his or her country, esp. one who is ready to support its freedoms and rights and to defend it against enemies or detractors. I hope this helps.

expats only live there for a while for work but migrants tend to stay there more permanently and may be there ddue to other reasons such as war

I think the semantic difference is expats are considered to be people who live abroad temporarily and will return to their home country. Whereas an immigrant is someone who inends to settle in the second country permanently. Migrant technically covers both scenarios. In practice, there is a habit, certainly in the UK, of referring to any British people who move abroad as "expats" rather than immigrants/migrants. This happens colloquially but also in the media. 

Expat is defined as someone who moves to another country temporarily for employment (so they move there and plan to move back home in, say, 2 years). Immigrant is someone moving to another country *permanently* Other comments have pointed out "Expat" has a "White wealthy foreigner" stereotype, but that mostly comes from white wealthy people historically generally being expats (moved only for business reasons), and people slowly adopting that term for if they fit the "typical" expat, even if they've moved permanently (like the British on the Spanish coast, many there call themselves expats when in reality they're immigrants)

An expat lives in another country but retains their original citizenship. A migrant moves to another country in the hope of becoming a citizen of that country.

Uh oh you discovered a very sociopolitical question

Technically an expat is temporary, a migrant is permanent. You will find this disputed a lot. A lot of people say it's racist and only white people are expats, but I grew up with plenty of brown expats around. The Thai and Indian and Phillipine embassy staff kids were in my school while their parents were on assignment. (Probably others too but I didn't know them personally.) There were Indian computer professionals, who worked with my Dad, too. They were not migrants, they went home to India. It does not help that some of the worst white people go live in cheaper cost of living countries, refuse to integrate with the locals in any way beyond having servants, and call themselves expats.

White person = expat Person of color = immigrant