Highly competent in at least 3 languages; general understanding of 5 others; good written communication and presentation skills; able to create gui; understanding of distributed systems and networking; unix command line; can at least rebase in git
A person might have zero experience except Node.js yet still show high mastery of functional programming, mixed OOP, design patterns, compilers, etc.
Setting any threshold on languages just sets up a meaningless metric.
If you have these skills there is a very high likelihood that you can do most other things that are thrown at you
Most of the other answers have all these high level wishy washy specifications, I thought I’d take a more brass tacks approach.
I suppose this list could be called necessary but not sufficient. The question is what does a master “look like”. If you can only work with one or two languages you are by no means a master.