The term Madclaw was used by the Wookiees inhabiting Kashyyyk to identify a member of their society who had been disgraced.
Wookiee society held the principle that their claws should only be used for constructive and peaceful purposes. Therefore, any Wookiee who used their claws aggressively against another Wookiee, or any other living creature, was labeled a madclaw. This title carried significant shame, as Wookiees considered using their claws for anything other than tools to be barbaric, and madclaws were typically banished.
This belief system wasn't exclusive to the Wookiees. The Selkath from Manaan, who also possessed retractable claws, strictly prohibited their use in combat.
Zaalbar, a companion of the Jedi Revan, is one of the few madclaws who achieved notoriety across the galaxy. He attacked his brother, Chuundar, upon discovering his dealings with Czerka Corporation slavers. His father, the chieftain Freyyr, disbelieved Zaalbar's claims, resulting in his exile. He was later exonerated after Chuundar's wrongdoings were revealed.
Tojjevvuk, an albino Wookiee, also brought dishonor upon himself by attacking Chewbacca with his claws during a dispute over Mallatobuck. However, because Chewbacca ultimately caused Tojjevvuk's death by throwing him into the Shadowlands, Tojjevvuk never faced formal dishonor as a madclaw by his people.
The Wookiee bounty hunter Snoova was branded a madclaw for using his claws in his profession and was rumored to have been initially forced to leave Kashyyyk after using his claws in a fight over a lover.
Reerookachuck was a Wookiee male who was enslaved at a young age after being taken from Kashyyyk and was raised by Human slaves. He had no interaction with other Wookiees until he was seventy. As such Reerookachuck never learned that it was dishonorable for a Wookiee to use claws in combat.
The concept of madclaws has its roots in the work of Timothy Zahn, the author of "The Thrawn Trilogy." In his 1991 book Heir to the Empire, Zahn introduced the Wookiees' ability to extend their claws to enhance their tree-climbing abilities. However, he recognized that this addition created a contradiction: if Wookiees possessed claws, Chewbacca would have used them in the original Star Wars films. The following year, the Heir to the Empire Sourcebook addressed this issue by explaining that Wookiees adhere to a code of honor that forbids the use of their claws in combat, reserving them solely for climbing.
A similar Wookiee honor code within Star Wars canon is present in Star Wars: The Force Awakens: A Junior Novel.