Is to be hungry an idiomatic expression?
"Idiom" can also refer to the characteristic manner of speaking in a language, also called its parlance. Parlance is a word which originates from the Latin root "parl-", to speak. An utterance consistent with a language's parlance is described as idiomatic. For example, "I have hunger" is idiomatic in several European languages if translated literally (e.g. German ich habe Hunger; French j'ai faim; Spanish tengo hambre or in Italian ho fame), but the usual English idiom is "I am hungry".Additionally, you can use the word "hungry" figuratively,
Figurative: She's hungry (for success).
Literal: She's hungry (for a meal).
All the best.