abstème: (n.) a priest who is exempted from drinking from the chalice because of an acute aversion to wine.
oblatif(ve): (adj.) placing the needs of others before one's own.
I'm not sure an English equivalent exists for the first, but there is the adjective 'abstemious', meaning "not self-indulgent, esp. when eating and drinking." It loses the religious aspect, though, which is sort of important here. The second might be best translated as 'agape'. In the Deus Caritas Est, a document written by the current Pope Benedict XVI, the distinction is made between possessive love (Eros) and unconditional, self-sacrificing love (Agape). But... is agape a rare/obscure word? Maybe not so much, with over 17 million hits on the trusty old Goog. Any other ideas?