Hmm. Well, it is definitely a word. But, for me at least, it's a positive nature-y association.
Moss has so many different shades of green and it's so soft. I kind of like it for the association. I definitely wouldn't be gutsy enough to use it as a first name, but it would make a rockin' middle name. I don't think it's unusable as a first name, though.
I saw you're getting a lot of naysayers. Maybe
Moss as a nickname?
Amos nn
MossMosi nn
MossMostyn nn
MossThomas nn
MossNicodemus nn
MossMorris nn
MossMorrison nn
MossMorpheus nn
Moss
Moss Emmanuel Moss EvanderMoss ElijahMoss OliverMoss Benjamin
Three boys nappin', one mama namenerdin'
To peruse my top 100ish names:
http://www.behindthename.com/pnl/82589
"My Inner Birthing Mother Paddles a Canoe" and other non-name musings
found on my blog:
http://jodifriesen.blogspot.ca/2014/07/paddle-power.html