subs. (common).A worthless animal; a fool; said of a horse it signifies a good-for-nothing brute; of a man or woman, a duffer, a rotter. [Most likely from the Scots CROCK = an old sheep.]
1887. The Sporting Times, 12 March, p. 2, col. 5. The wretched CROCKS that now go to the post will be relegated to more appropriate work.
1889. Bird o Freedom, 7 Aug., p. 3. For five minutes that CROCK went about twice as fast as it had ever done.
1889. Illustrated Bits, 13 July, I say, said the Lumberer to the Old Hermit, as they stood at the mouth of the Cave listening to the song birds, you are getting a bit of a CHOCKfailing fast, I should say.