I'd call 'em compound adverbs. A perennial question, owing much to the unsystematic orthography that English has been saddled with, is when to use hyphens, spaces, or nothing at all. Why pick on adverbs or conjunctions, while passing over nouns and other parts of speech in silence? Why babysitter instead of baby-sitter, or into instead of in to? Why do not but cannot? And baseball used to be base-ball, but it changed a long while ago. The list is endless.

Ceci n'est pas un seing.