Permissive and Copyleft Are Not Antonyms
Using the term "permissive" as an antonym to "copyleft" - or "restrictive" as its synonym - are unhelpful framing. Describe license reciprocity instead. Some open source licenses implement a clever hack invented by Richard Stallman where, as a condition of the copyright license, anyone creating derived versions has to agree they will license the new...
Meshed Insights Ltd
Deprecating "weak", "strong", "permissive" and "restrictive"
Some things never change, and one of them is certainly the usage of the terms in the title to describe open source licenses. They are all unhelpful terms that set frames which deceive developers about the impact of the associated licenses, as this article explains.