Dan Brown was probably in need of a good dictionary:
http://itre.cis.upenn.edu/~myl/language ... 00844.html
http://itre.cis.upenn.edu/~myl/language ... 01622.html
http://itre.cis.upenn.edu/~myl/language ... 01628.html
http://itre.cis.upenn.edu/~myl/language ... 01631.html
http://itre.cis.upenn.edu/~myl/language ... 01684.html
(The above links are from first to most recent)
Your lexicon isn't inadequate at all, William, I don't know what 'gnosis' or 'sfumato' mean (although I might be able to guess from context if I could see them in the novel).
As for the rest of the words, 'mortification' is (along with other "possible" forms such as 'mortify', 'mortifying' etc), I feel, much rarer than 'mortified', larger dictionaries only list these extra (often unattested) forms because they want to look more impressive than competitors. I'm sure that a learner could work out the meaning of these other forms from just a knowledge of 'mortified', by examining the context and seeing what the part of speech was.
'Unorthodoxy' is related to the more frequent 'unorthodox', the latter quite a useful word, but there are doubtless easier ones in your thesaurus that you recognize and could use just as profitably instead.
'Calices' is perhaps a misspelling of 'chalice', not that useful outside the context of religious theme, and fantasy, novels.
All of the following are good to know if you watch horrow movies where good fights evil against a religious backdrop: 'altar' (pagan sacrifices, black masses!), 'crucifix' (ward off those vampires, one can also say 'cross': to cross oneself, make the sign of the cross etc), 'stigmata' (so-so movie).
'Sacrosanct' is an interesting word, it is kind of like a combination of holy+respect. You might see it in the news from time to time describing people's
rights:
New Oxford D and T of E: the rights of parents are sacrosanct for this government; the individual's right to work has been upheld as sacrosanct.
Cambridge Advanced Learner's Dictionary: HUMOROUS thought to be too important or too special to be changed: I'm willing to help on any weekday, but I'm afraid my weekends are sacrosanct.
COBUILD 3: sacrosanct
If you describe something as sacrosanct, you consider it to be special and are unwilling to see it criticized or changed.
Freedom of the press is sacrosanct and should remain so
...weekend rest days were considered sacrosanct.
ADJ-GRADED: usu v-link ADJ
= sacred