MEANING:
noun: A habitual faultfinder or complainer.
ETYMOLOGY:
After Smelfungus, a hypercritical character in Laurence Sterne's 1768 novel, A Sentimental Journey through France and Italy. Earliest documented use: 1807.
USAGE:
"And a couple of smellfungus from the Official Paper ... carped that Issel chose to jump when the schedule reached its toughest stretch."
Paige Woody; Issel is the Wrong Scapegoat in Nuggets' Mess; Denver Post; Feb 13, 1995.