It means clothes.
It was more widely used centuries ago, because it had several senses, based on its Old French source, habillement or abillement, which come from the verb habiller, to fit out or render some item fit for service. The form without the initial h shows its link with English able, which comes from the related French habile or hable.
One early sense was of the outfit of a warrior — his weapons, munitions and other equipment of war (Shakespeare’s Richard II says: “Marshal, ask yonder knight in arms, / Both who he is and why he cometh hither / Thus plated in habiliments of war.”) This died out in the seventeenth century but another survived, the garments or vestments appropriate to some occupation, occasion or season.
Madame Lavalliere afterward admitted, that Maria Monk did arrive at her house at the time specified, in the usual habiliments of a Nun, and made herself known as an eloped Nun.
Awful Disclosures, by Maria Monk, 1836.
That association might make one think that habit, another word for the costume of a nun, was a short form of habiliments. Habit is certainly a shortening, but of habitual, because the costume or uniform was one that was customarily or habitually worn.
Habiliments is too pompously formal to fit our age and most dictionaries mark it as archaic. However, it also became a jokey way to refer to one’s everyday clothes and it may still be found as a humorous, dismissive or sarcastic way to refer to clothing:
You know the kind of cyclist I mean: all is vanity. ... He wears wicked shades, an insect-head helmet, and has athletic signage on his inappropriate habiliments.
The Herald (Glasgow), 20 Jun. 2014.