(n.) giving up hope from one form of salvation, and putting all hope in a different source instead
When one source of salvation fails you and you switch your interests to another source of hope, that’s called apocarteresis. (Pronounced with the stress on the –ter–, by the way.)
That’s hardly an everyday word, of course (nor, hopefully, an everyday occurrence). Instead, this is a term snatched from the world of literary analysis and rhetoric. Strictly speaking, the term apocarteresis applies to a scene or moment in a story in which a character is faced with abandoning one source of hope or inspiration, and changing their outlook to another. Else, it describes a figure of speech in which someone renounces one hope of salvation, and focuses on another.
That’s not to say that it can’t be used outside of the world of textual analysis, of course, it’s just the opportunities to casually drop a word like apocarteresis into conversation are probably fairly thin on the ground.
Etymologically, it’ll come as little surprise that apocarteresis is Greek. The prefix apo– comes from a Greek word essentially meaning ‘from’, and is typically encountered in English in words to do with turning or separating oneself from something larger or greater. You’ll find it or one of its variations, for instance, in words like apoplexy (a fainting fit—literally ‘struck from’), apostle (a messenger—literally ‘sent from’), and even apocalypse (which essentially means ‘from beneath a cover’—hence a revelation).
The rest of the word comes from karteresis, a Greek word for bearing or enduring something patiently—which oddly points to another somewhat less pleasant use of this word in antiquity.
Aside from its use in literature and rhetoric, the word apocarteresis was also used in Latin to describe death by intentional starvation. While the two meanings may appear unrelated, the undercurrent of someone giving up on one form of salvation and, in desperation, turning to another nevertheless links them together.