- a piece of computer hardware or software, or a computer system, that is clumsily designed or improvised from mismatched parts
- any poorly designed device or system
Today, the terms kluge and kludge are widely believed to be alternative spellings for the same word, although a distinction in usage can perhaps be detected: in the U.K., the connotation of kludge is almost wholly negative (as befits its alleged derivation), while U.S. usage, following the older spelling kluge and the alleged German derivation, admits some fondness for the cleverness or functionality underlying a kludge that works.
Ample jokes have been made about how these terms self-referentially apply to their own tangled history.
U.S. military slang, probably from the German klug (“clever”).
Cf. German Klōß, diminutive Klößchen "clod", Low Saxon klut, klute, Dutch kluit, perhaps related to Low German diminutive klütje "dumpling, clod", Danish Jutland dial. klyt "piece of bad workmanship, kludge", and Standard Danish kludder "mess, disorder". If so, related to klutz.
There is also speculation that the term was influenced by a particular, old, allegedly complicated printing press paper feeder manufactured by the company of Brandtjen & Kluge.