I want to ask whether any materials that has Free for non-commercial use license can be used in a GNU GPLv3 licensed software.In my opinion, it is free for non-commericial use, and GNU GPLv3 is also non-commericial, so it can be used in the software,  is it?I'm asking this question because there are no explicit or clear declaration about FREE FOR NON-COMMERCIAL USE license out there....
Is Free for non-commercial use license compatible with GNU GPLv3 license?
licensing;gpl
Definitely not.  GPLv3 allows for both commercial and non-commercial use.  Other than the license itself, which does not restrict commercial use, see this GPL FAQ answer:Q: If I use a piece of software that has been obtained under the GNU GPL,  am I allowed to modify the original code into a new program, then  distribute and sell that new program commercially?A: You are allowed to sell copies of the modified program commercially,  but only under the terms of the GNU GPL. Thus, for instance, you must  make the source code available to the users of the program as  described in the GPL, and they must be allowed to redistribute and  modify it as described in the GPL.Also there is this page about selling free software, which is not talking about the GPL specifically.