Apostate, that sounds just right.
As far as Pope Francis, I think it's polite to uniformly call him by this title, without using the word 'Papist' which is so 'dated.
Seems dated, as in "19th Century Angry Anglican'. { I got that idea from reading the link posted by Archimandrite Nilos about
the Grafton character and Patriarch Tikhon [Bellavin].
Besides, what if Catholics arrive at this Forum hoping for a refreshing change from Vatican II Plastic,
and catch sight that derogatory term ? They would be turned off in a second and NEVER consider ANY Orthodoxy, let alone True Orthodox churches.
Maybe I will be turned out in a second for venturing this idea ---!
I think it's quite wise to stay with the correct protocol.
I don't like seeing the secular/atheist media write ' pope ' without a capital letter, it's the SAME old
prejudices ; neither do I like seeing the word Mass spelled mass ; a not subtle attempt to demean the Roman Liturgy.
Or convey the idea that it is something only for the dumb, unsophisticated "masses" of believers.