"to cut with a quick blow," mid-14c., of uncertain origin, not found in Old English, perhaps from Old North French choper (Old French coper "to cut, cut off," 12c., Modern French couper), from Vulgar Latin *cuppare "to behead," from a root meaning "head," but influenced in Old French by couper "to strike" (see coup). There are similar words in continental Germanic (Dutch, German kappen "to chop, cut").
Related: Chopped; chopping. Chopping-block "block of wood on which anything (especially food) is laid to be chopped" is from 1703.
"shift quickly," 1530s, earlier "to bargain" (early 15c.), ultimately from Old English ceapian "to bargain" (see cheap); here with a sense of "changing back and forth," probably from common expressions such as to chop and change "barter." To chop logic "engage in sophistical argument" is recorded from 1570s. Related: Chopped; chopping.
mid-14c., "act of chopping, cutting with a quick blow," from chop (v.1). Meaning "piece cut off" is mid-15c.; specifically "slice of mutton, lamb, or pork" (usually cut from the loin and containing the rib) is from 1630s, probably from being "chopped" from the loin. Sense of "a blow, strike" is from 1550s. Specific cricket/baseball sense of "a downward stroke with the bat" is by 1888.