"to cut roughly, cut with chopping blows," c. 1200, from verb found in stem of Old English tohaccian "hack to pieces," from West Germanic *hakkon (source also of Old Frisian hackia "to chop or hack," Dutch hakken, Old High German hacchon, German hacken), from PIE root *keg- "hook, tooth."
Perhaps influenced by Old Norse höggva "to hew, cut, strike, smite" (which is unrelated, from PIE *kau- "to hew, strike;" see hew). Slang sense of "cope with" (as in can't hack it) is first recorded in American English 1955, with a sense of "get through by some effort," as a jungle (phrase hack after "keep working away at" is attested from late 14c.). To hack around "waste time" is U.S. slang, by 1955, perhaps originally of golfers or cabbies. Related: Hacked; hacking.