early 14c., from Old French (h)able (14c.), from Latin habilem, habilis "easily handled, apt," verbal adjective from habere "to hold" (see habit). "Easy to be held," hence "fit for a purpose." The silent h- was dropped in English and resisted academic attempts to restore it 16c.-17c., but some derivatives acquired it (e.g. habiliment, habilitate), via French.
Able-whackets - A popular sea-game with cards, in which the loser is beaten over the palms of the hands with a handkerchief tightly twisted like a rope. Very popular with horny-fisted sailors. [Smyth, "Sailor's Word-Book," 1867]