What does Boxing Day have to do with boxing?
1610s, "meddlesome, impertinently busy," short for earlier pragmatical, or else from Middle French pragmatique (15c.), from Latin pragmaticus "skilled in business or law," from Greek pragmatikos "fit for business, active, business-like; systematic," from pragma (genitive pragmatos) "a deed, act; that which has been done; a thing, matter, affair," especially an important one; also a euphemism for something bad or disgraceful; in plural, "circumstances, affairs" (public or private), often in a bad sense, "trouble," literally "a thing done," from stem of prassein/prattein "to do, act, perform" (see practical). Meaning "matter-of-fact" is from 1853. In some later senses from German pragmatisch.