Como dizer "católico não praticante" em inglês

Olá hadryanne,

Some state that a non-practicing Catholic is a Catholic by name only. That is false! He may have been baptized as a Catholic but if he no longer practices his faith according to the teachings of the Catholic Church, he can no longer claim the honour of being a "Catholic." He can only claim that he "was" a Catholic.
Source: catholicdoors

I am one who should go to church more often.

Welcome to EE forum!

I use the term "retired Catholic".

Thomas/US

Lapse Catholic:

Ref. en.wikipedia
Ref. lexico
Ref. dictionary.cambridge

In Portuguese "um católico não praticante" is an expression to define a "lurking" kind of people, the ones that go to the Mass at weekends or some special dates, festivities, marriages etc.
The term, of course, is shunned by some, they saying you are a non-practicing is tantamount to say non-chatolic, since you don´t say you are a non-practicing vegan, a non-practicing, non-practicing athlete, etc.

Lay people would state that they are 'non-practicing' nonetheless. It´s in their family tradition, they go to services from time to time, etc.

It seems, from the previous comments that "non-practicing" trigger the same reaction in English, seems like in English "non-active Chatolic" is a more 'fitting' (acceptable) word, or at least it doesn´t cause the same feeling.