noun

religiosity

rih-lij-ee-AH-suh-tee/rɪˌlɪdʒiˈɑːsəti/

The degree or quality of religious belief or practice.

The man's earnest private prayer expresses his religiosity.

A young adult Latino man kneels in earnest private prayer at a simple church kneeler, eyes closed and hands clasped, conveying deep religious devotion.

Etymology

Religiosus described someone pious or devout; the noun ending makes that devotion a quality or state. The selected sense emphasizes the strength of religious feeling or commitment.

In context

Dad Saves America167:07

have gotten more religious. Uh the secular part of the right has become kind of dead on the vine. Um, so you have this desire for this sort of rising religiosity

I Interviewed the 9/11 Mastermind’s Family. Here’s What I Discovered. - Richard Miniter

More examples

The survey measures religiosity through questions about belief and worship.
His religiosity deepens during difficult times.
Regular attendance alone does not reveal a person's religiosity.

Forms

religious adjective — Relating to religion or showing religious devotion.

Similar words

piety: Emphasizes reverent devotion rather than the degree of religious involvement.
devotion: Emphasizes deep commitment and need not refer to religion.