A "hobby writer" refers to someone who writes just for fun or as a personal interest, rather than as a profession or for earning money. Full definition
Fresh Ink Fresh Ink is a novice contest designed for new hobby writers who have not yet been published. (publishersarchive.com)
If there weren't so many hobby writers willing to sell their poorly edited manuscripts for a song, serious writers would have an easier time making a living. (rjeliason.com)