Goblins are short, humanoid creatures.
According to Wiedźmin: Gra Wyobraźni PnP RPG, goblins, also known as kobolds, gnome-sized, savage, mischievous humanoid creatures that live mostly underground. They hate daylight and are active above ground only during the night. A goblin isn't really dangerous, but can be quite a pest. They piss into people's milk, vandalize houses or steal chickens.
Other work of Andrzej Sapkowski Edit
Some forest kobolds inhabiting an abandoned lumberjacks' glade near Ktova village appear in chapter eleven of the Warriors of God novel. Shortly after his escape from the Trosky Castle, Reynevan is ambushed by about twenty of them; they are described as hirsute creatures being as short as human children, having short legs, long arms and ugly, doggy faces.
They are featured similarly in his The Eye of Yrrhedes role-playing game. Mountain kobolds from tribe of the Crookednose are 1.20 meters tall, have dog faces and, contrary to the forest ones from the Warriors of God, hairless reddish skin. They wear leather and fur clothes and are armed with yatagans, cudgels and light crossbows. Despite their good eyesight in the darkness, they still illuminate their habitats with oil lamps and lanterns treating them as the luxurious decoration. Cruel brigands, attack without hesitation when have advantage. They peculiarly hate gnomes, being with them in a ceaseless state of war.