Pewnkah was a widely used derogatory term meaning "low-life."
When D'Argo and Lo'Laan Tal had settled on Havenik and begun farming, a merchant in the market told them that the way he stayed "well-respected is not to deal with filthy alien pewnkahs!" D'Argo reacted by beginning to enter a state of hyper-rage before Lo'Laan calmed him down. ("A Many-Splendor'd Thing")
Later, when Lo'Laan was pregnant with Ka Jothee, Tijo commented that "this good Sebacean woman's gotten 'erself knocked up by this filthy alien pewnkah Luxan type gennleman, she 'as!" ("Brotherly Hate")
While searching for D'Argo on 7-Hetch-1-Bralk, Macton Tal spoke under his breath, referring to Kris W'Lash as a "filthy pewnkah of a bureaucrat," before being interrupted by Sergeant Ravan. ("The Long Tenka of the Law")
During D'Argo's trial for the murder of Lo'Laan, Admiral Josbek referred to the situation with the Peacekeeper Judicium by noting that "Too many Sebaceans are consorting with Aliens. Lieutenant Tal's sister even procreated with this Luxan pewnkah. It needs to stop." ("Error and Trial")
After Rygel had been captured, Bishan proclaimed to Hyneria that "a filthy group of pewnkahs, led by a Luxan/Sebacean halfbreed abomination and a devious Nebari tralk, attempted a coup, but they were unable to overcome the glorious forces of Hyneria." ("Dungeons and Dominars")