Is Bitter Sweet hyphenated?

Compound words

bitter-sweet or bittersweet?). Compound adjectives that are set phrases are not usually hyphenated, except to avoid ambiguity (the tax office ruling was challenged by a foreign-office lackey).

Is it bittersweet or bitter sweet?

The adjective bittersweet describes a taste that is a blend of bitter and sweet. Bittersweet chocolate, for example, contains more chocolate and less sugar than milk chocolate or even semisweet chocolate. The adjective bittersweet doesn't just refer to taste.