I can see this name as unisex. HEAR ME OUT!Moss' past use as a Jewish name is without a doubt, 100% masculine (though it seems to be archaic even in that aspect - a Jewish boy today, especially in the U.S. where I am, would more likely be named Moses or Moshe). But as an English-language name, it can either be derived from Moses (which was its medieval use), or from the plant: https://en.wikipedia.org/wiki/Moss#/media/File:Tionesta-ac-moss2.jpg.It's a carpet plant, flowerless, but still surprisingly beautiful. And since English does not have gendered nouns, just about every name from nature (other than perhaps the flowers) can be considered unisex.Yes, Moss is one letter off from Ross, but the vowel sound is also quite similar to Maud / Maude, a feminine name from the Middle Ages. I think Moss can work as a feminine name, provided it's paired with a very feminine middle name (otherwise it'll look a little "tryhard" and like a political statement to reject the feminine).
It can also mean simply "moss" in English, as in the plant. I think Moss is a beautiful name, though I think of it as a girl's name, at least in the moss, the plant, meaning of the word.
He is a nerdy, pure-hearted, awkward, and hilarious character.