* Infatuation: This is the most common and direct way to express the noun form of "infatuated". It refers to the state of being deeply and uncritically in love with someone.
* Infatuation with: You can also use "infatuation" as a noun followed by a prepositional phrase specifying the object of the infatuation. For example, "His infatuation with her was obvious."
* Object of infatuation: This phrase refers to the person or thing that someone is infatuated with.
Ultimately, the best way to express the noun form of "infatuated" depends on the specific context of your writing.