Pace

languagehat.com: PACE.:

I have always pronounced the preposition pace ('with due deference to' or 'despite,' from the ablative of Latin pax) in the traditional anglicized way, PAY-see, and assumed that was the universally accepted pronunciation. Now I discover, having seen the casual aside “Pace (that is to say, aloud, pa che)” in this Pepys Diary thread, that the Church Latin version, PAH-chay, is equally acceptable (the OED gives it second place for U.K. usage, first place for U.S.). So it's time for another Languagehat straw poll: if you use this slightly obnoxious Latinism, how do you say it?

You mean the right answer isn't "payss"? Good thing I've never pronounced it!