Inactive
From MormonWiki
Inactive or Inactivity is the term members of the Church of Jesus Christ of Latter-day Saints use to describe someone who is not participating in the Church, but who is still on the Church records. Generally speaking, these are individuals are not attending church or are otherwise not involved in church activities (See also Less Active, and Active).
The Jewish equivalent would be "non-observant." The Catholic equivalent would be "non-practicing."