“John’s so sensitive!”
“Ouch! My teeth are really sensitive!”
If you (or your teeth) are sensitive, it means they have a lot of feeling. They’re really full of feeling. That is, they are feelingful.
“You’re more feelingful than your brother”
“He’s the most feelingful person I know!”
NOT: feelingfuller, feelingfullest. We don’t say “resentfuller” or “beautifullest”.
The negative can be formed with un-: unfeelingful. That is, “insensitive”.
That’s it! A new English word for you formed totally regularly from the tools already available to us.
© 2020 Bryan A. J. Parry