A fake but funny-sounding attempt to use heavy as a noun ("heaviness" would be standard.)
From 1977 Academy Award winning film ANNIE HALL, screenplay Woody Allen and Marshall Brickman:

Alvy Singer (Woody Allen) to girlfriend re rock concert:

"Was it heavy? Did it achieve . . . um, heavyosity?"
by al-in-chgo March 7, 2010
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