The first thing that pops into my head is “tzom kal,” because no one in America calls it a “tzom” – they call it a “fast day.” Only in Israel have I heard it referred to it as a “tzom,” and then usually with the appendage “kal,” resulting in the greeting “tzom kal” – may you have an easy fast.
There’s been a trend of late to wish others an “easy and meaningful fast,” and, as lovely and pious as that seems, it always kind of rubbed me the wrong way. I wasn’t sure why, until I read something somewhere about Rabbi Yisrael Salanter. He famously posited that “Yenem’s gashmius is deine ruchniyus,” someone else’s material needs are your spiritual needs. What this means is that most people worry about filling their own material needs, and making sure others are up to par spiritually. No. You worry about your own spirituality, but make sure others’ physical needs are met (which is your spiritual concern).
So, just wish others an easy fast, and leave the “meaningfulness,” the spirituality, to them! (Do worry about your own meaningfulness!)