Anona queried
inaner being common. Recently I re-classified
urbaner and
urbanest as rare, based on their extremely infrequent appearance in text samples. The same consideration applies to
inaner and
inanest.
They are used occasionally, as in this passage from 2004 when
Washington Post columnist Tom Shales was describing the television coverage of Ronald Reagan's funeral:
There were also the usual giddy weather reports and inane remarks, none inaner than that of a Fox 5 reporter stationed at the Capitol and anticipating a big crowd: "If you've ever been to Disney World," he told viewers, "you've probably got an idea of what they've got going here."
However, they're definitely not common, so I'm changing them for future puzzles.