Answer:
Sourdough
Step-by-step explanation:
A compound adjective is an adjective made up of two or more words, in which either of those words can be a noun, an adjective, an adverb, a verb in their past participle form or a verb in their present participle form. This type of adjectives words may be joined by a hyphen or they may not like the "sourdough" word, which it's a compound adjective made up of the adjective "sour" and the noun "dough", that describes the noun "bread."