The symptoms of OCD have been known for a long time. Who can forget Lady Macbeth at the sink, scrubbing away at the imagined evidence of her guilt. But the term obsessive-compulsive disorder is a relatively recent one. In the seventeenth and eighteenth centuries, obsessive thoughts were ascribed moral significance, hence the term "scrupulosity." In the early nineteenth century, Esquinol described OCD as a "monomania." French psychiatrists of the age used the term "folie impulsive" (impulsive insanity) to describe the symptoms we now term OCD. Perhaps the most mellifluous terminology came from the Germans. The psychiatrist Griesenger described his cases of OCD as "Grubelnsucht" (ruminatory or questioning illness). But it was from the German psychiatrist Westphal's use of the word "Zwangsvorstellung" (compelled presentation or idea) that we seem to have gotten our current terminology. The British translated it as "obsession" and on our side of the pond it was "compulsion." In the best tradition, we were able to compromise, and arrived at obsessive-compulsive disorder.

Source: http://ocd.stanford.edu/subphistory.html