Short form of Malcolm, from Gaelic 'maol Colum' meaning devotee of Saint Columba.
Mal most commonly serves as a short form of Malcolm, the Anglicization of the Scottish Gaelic Máel Coluim, meaning "devotee of Saint Columba" — the Irish monk who brought Christianity to Scotland in the sixth century. Malcolm was a royal name in medieval Scotland: four Scottish kings bore it, most famously Malcolm III (Malcolm Canmore), whose eleven-year-old son would be immortalized by Shakespeare as the rightful heir in Macbeth. The compressed form Mal carries all of this heritage in a single syllable.
Mal also functions as a diminutive of Mallory (from the Old French malheureux, meaning "unfortunate" — a characteristically medieval habit of giving children fatalistic names as a ward against bad luck) and, less commonly, of names like Malachi or Malvin. In mid-twentieth-century jazz, Mal Waldron (1925–2002), the pianist who served as Billie Holiday's accompanist in her final years, gave the name a cool, introspective musical identity. The name gained a vivid contemporary life through Firefly, Joss Whedon's cult science-fiction series, whose Captain Malcolm Reynolds — "Mal" — became a cultural archetype of roguish, principled heroism, introducing the name to a new generation.
The Latin prefix mal- meaning "bad" gives some parents pause, but historically the name has shed that association entirely in standalone use. Today Mal functions as a confident, gender-flexible short form — used independently for both boys and girls — that feels modern in its brevity while carrying surprisingly deep Scottish and medieval roots. It is the kind of name that wears its history lightly.