在巴尔干地区，法外之徒（Hajduk、Haiduk、Haiduc、Hayduck、Hayduk）所用以指代者，或不在法律保护范围内之犯人，或土匪，或对付奥斯曼帝国的自由斗士。此词有不同写法，现列如下：haiduc（罗马尼亚语）、hajduk (阿尔巴尼亚语）、хајдук/hajduk (塞尔维亚语), hajduk（波兰语）、ајдук (ayduk，马其顿语）、хайдут（haidut，保加利亚语）、aiducco（意大利语）、haïdouk（法语）、haydut（土耳其语）、hajduk（波斯尼亚语）。

Hajduk is a term most commonly referring to outlaws, brigands, highwaymen or freedom fighters in Southeastern Europe, and parts of Central and Eastern Europe.

In Balkan folkloric tradition, the hajduk (hajduci or haiduci in the plural) is a romanticised hero figure who steals from, and leads his fighters into battle against, the Ottoman or Habsburg authorities. They are comparable to the English legend of Robin Hood and his merry men, who stole from the rich (which as in the case of the hajduci happened to be also foreign occupants) and gave to the poor, while defying unjust laws and authority.