The Condrusi were a Germanic tribe of ancient Belgium, which takes its name from the political and ethnic group known to the Romans as the Belgae. The Condrusi were probably located in the region now known as Condroz, named after them, between Liège and Namur. The terrain is wooded hills on the northeastern edge of the Ardennes.
The Belgae were distinguished from the Celts and apparently claimed to be of Germanic descent. From Belgic names we know that the Belgae were heavily influenced by the Gaulish language, but from other information we know that they were also heavily influenced by Germanic peoples on the east of the Rhine river. In particular, the Condrusi were in the tribal group known as the Germani cisrhenani, who are amongst the Belgae most strongly associated with Germanic ancestry.
We learn all we know about the Condrusi from Julius Caesar in Commentarii de Bello Gallico. In 2.4, Caesar states that the Belgian Germani had crossed the Rhine long ago to take control of the fertile land on the other side. They kept a distinct identity, and a reputation for military strength, because they were the only Gauls who successfully resisted the Cimbri and Teutones during their migrations in the second century BCE.
Whether the Germani cisrhenani in Belgium actually spoke a Germanic language, is uncertain, but in any case it was claimed by Tacitus that these Germani were the original Germani, and that the term Germani as it came to be widely used was not the original meaning. He also said that the descendants of the original Germani in his time were the Tungri.