noun
doujin software; hobbyist software
Refers to software, especially video games, created by hobbyist circles (同人サークル) rather than commercial companies. Often distributed at events like Comiket.
彼は趣味で同人ソフトを作っている。
He makes doujin software as a hobby.
コミケで面白い同人ソフトを買った。
I bought an interesting doujin software at Comiket.