A Lubbockian slime devil was a loathsome creature. To call a person a Lubbockian slime devil was a grave insult.
After Go'en C'ullho tried to assassinate Ra'ch B'ullhy, Du're C'ullho referred to it saying, "that Lubbockian slime devil took an oath to protect the people of this city. It just violated that oath by trying to kill one of them in cold blood." (TNG - Perchance to Dream comic: "In the Sleep of Death, What Dreams May Come")
Martok referred to the Changeling that had taken his place prior to the Dominion War as a Lubbockian slime devil, as did Commander Kurak of the IKS Gorkon in reference to her assistant engineer, Vall. (TNG novel: Diplomatic Implausibility)