Apostatize v. i. (past & past part. apostatized; pres. part. apostatizing) To renounce totally a religious belief once professed; to forsake one's church, the faith or principles once held, or the party to which one has previously adhered.
... that backsliding is in any sense advantageous to spiritual development, but it is our certain destiny if we do not assiduously employ the means necessary to our growth in grace. By backsliding is meant the gradual turning back or away from God; to apostatize. The Savior gives us warning to "watch and pray," that we "enter not into temptation." The tempter will lay in your pathway all things possible to induce you to turn away from God. He will suggest that it is not necessary to pray so much, ... — The Gospel Day • Charles Ebert Orr
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