Mcavity rhymes with:
cavity, cavity, depravity, gravity, activity, brevity, captivity, cavity, conductivity, creativity, depravity, exclusivity, festivity, gravity, insensitivity, longevity, nativity, negativity, proclivity, productivity, progressivity, radioactivity, reactivity, relativity, selectivity, superconductivity, velvety
Mcavity sounds like:
macbeth, makeshift, mcbeath, mcbeth, mcfate, mckevitt, megabit, megabyte, megafood, messagepad, misbehaved, misfit, mousepad, mukhopadhyay, muscovite