What parts of speech is the word falling action?

The phrase "falling action" is a noun phrase, acting as a single unit.

Let's break down the individual words:

* Falling: This is a present participle of the verb "to fall," acting as an adjective modifying "action."

* Action: This is a noun, the headword of the phrase.

Therefore, "falling action" is a noun phrase, specifically functioning as a compound noun.