hand-hacking n. 1. [rare] The practice of translating {hot spot}s from
   an {HLL} into hand-tuned assembler, as opposed to trying to coerce the
   compiler into generating better code. Both the term and the practice are
   becoming uncommon. See {tune}, {bum}, {by hand}; syn. with v. {cruft}.
   2. [common] More generally, manual construction or patching of data sets
   that would normally be generated by a translation utility and
   interpreted by another program, and aren't really designed to be read or
   modified by humans.


Source: The Jargon File