It depends on how you're using the word climax. It can be a noun eg. the climax of the film/play.
noun
The word 'climactic' is the adjective form for the noun climax.
climax is the climax of the climax and the climax or the climax
An appositive is a word or phrase that renames or gives context to a noun right beside it. They are often used to provide emphasis, or build climax.
the climax of the story
The address of the Climax Library is: 104 W Broadway, Climax, 56523 1234
what is the climax of the book the three musketeers
you get a climax by being in a community
climax
A climax that is creative.
Climax of maid in Manhattan is a romantic climax. In the big romantic climax, they kiss without verbally resolving anything.
"Falling action" is a noun phrase, specifically a compound noun. It refers to a stage in a narrative that occurs after the climax and before the resolution, where the story begins to wrap up. In this context, "falling" functions as an adjective describing the type of action.