Though the edition of Merriam-Webster's Dictionary I consulted lacks a specific entry for "unscented", the addition of the prefix "un" to a word either means "to deprive of" or "to be free of".
So in the dictionary world, "unscented" either means:
- to be free of scent
- to have the scent removed from
The Coconut Coast Natural Products' soap glossary backs the first definition up; they say that an "unscented" soap is a soap to which no fragrance has been added. Presumably, though, such soaps can have an odor from raw ingredients such as coconut oil.
This seems painfully logical, doesn't it? Something that's unscented contains no scent.
This distinktion is important to me personally, because I (like a nontrivial number of other people) am allergic to some perfumes; the cheap ones seem to cause the worst reactions but even high-priced, refined fragrances can be trouble.
So, you can imagine my irritation when I tried out a recently-purchased bottle of unscented Suave brand hairspray and discovered it emitted a noxious, flowery fog that sent me into a sneezing fit. Even if I hadn't been allergic to it, the fact that it made me smell like I'd spent the night in a French whorehouse was a problem.
Had I misread the front label, thinking it said "unscented" when in fact it said "unbearable"?
Nope. The stuff was supposed to be unscented. I turned it over and read the ingredients. Second to last item: fragrance.
So I sent Suave an email query. A customer support rep snottily replied that the U.S. cosmetics industry standards state that products labelled "unscented" can contain a "masking" fragrance. How strong that fragrance can be is apparently up to the discretion of the individual manufacturer.
The semantic difference the cosmetic industry sees between "unscented" and "fragrance-free" escapes me. So does the rationale of labelling any products with added fragrance as "unscented" when I've seen plenty of other products labelled "lightly scented", which seems a far more accurate representation of what most masking fragrances are supposed to do.
At any rate, if you're looking for cosmetic products that are really and truly unscented beyond their functional ingredients, you need to look for products that are labelled "fragrance-free". | 
