1. casuist - Noun
2. casuist - Verb
To play the casuist.
Source: Webster's dictionaryFrom it, the casuist would ask how closely the given case currently under consideration matches the paradigmatic case. Source: Internet
The casuist might conclude that a person is wrong to lie in legal testimony under oath, but might argue that lying actually is the best moral choice if the lie saves a life. Source: Internet