I say "Catholic" and, if someone looks affronted, I quickly add "with no guitars".
When speaking of a NO Catholic, I merely say, "[Person] attends [NO parish]" and that usually explains that. The ones I refer to most commonly (acquaintances) usually identify with another belief-system, like Buddhism, or sometimes I learn of a surprise addition to their belief system, and I bite my tongue from saying what I think ("new age catholic") and just leave.
Catholic is Christian, but Christian in common parlance isn't always Catholic because apostolic succession, or at least that's how I was taught. (Catholic, not anathematized, is where we want to be; someone raised Protestant who is Baptised, and otherwise does the best they know how in this evil age, hopefully will at least fall under invincible ignorance, and EENS/Church, but I'm not dogmatic at all on what exactly constitutes "the Church on earth" in this age. I think Baptism is pretty necessary unless you live in the bush somewhere in Africa.)
Yeah, I like Catholic.