DANIEL E. answered 03/21/19
Adaptable and Flexible French Tutor - All Levels of Proficiency
These terms are indeed used interchangeably but there are some subtle differences. For example, I would not use "neanmoins" (nevertheless) instead of any of the others to mean "however." I don't think "nevertheless" and "however" in English mean quite the same thing. Following are some other subtleties:
"En revanche," "par contre," and "d'autre part" (which you did not mention) are more akin to "on the other hand" which I don't think equates to "however" in English.
"Pourtant" is more akin to "yet" which I don't think equates to "however" in English.
"Cepandant," "pourtant," and "toutefois" most closely equate to "however" in English.
I would suggest that obsessing about these differences is not going to help you learn the language. Instead, once you learn the language, you can be more selective as to which word you would use in a particular context. In French, context is a big factor in deciding which similar-meaning word is going to fit the best.
If you think about it, there aren't too many words in English that can be used interchangeably with "however." In French, however, subtle differences are the order of the day and what make it such a rich, beautiful, and melodic language. The French expression "Vive la Difference" says it all.
I hope this helps and Bonne Chance!