The term "liberal" in "liberal arts" originally meant "appropriate for free men," i.e., those citizens of the republics of classical antiquity and a generalized education thought to be most proper for these social and political elites. As such, the course of study in the "liberal arts" was almost entirely devoted to the classics while shunning most training directly applicable for a given trade or pursuit. Later, the "liberal arts" broadened to encompass study in the humanities more generally.
Liberal arts colleges are still typified by their rejection of more direct vocational training, with graduates often leaving to pursue more specialized training at other institutions, such as professional (ie, business, law, medicine) or graduate schools.
Today, the liberal arts are sometimes, e.g., in college course catalogs, treated as "liberal" in the sense of being liberating of the mind, removing prejudices and unjustified assumptions; this, in spite of the etymology, is treated by some as the central meaning of the term.