crack’d in the ring Flawed or imperfect at the perimeter or edge; of little value or use; (of women) nonvirginal. This expression, popular during Elizabethan times, is no longer used today. It was limited in application to money, artillery, and (figuratively) to women.

diamond in the rough One whose unrefined external appearance or ungraceful behavior belies a good or gentle character and untapped potential. This expression derives from the disparity between a diamond in its natural state, before being cut and polished, and in its refined state, when it has become an impressive gem. Analogously, graceful manners and social amenities can be learned. Diamond in the rough dates from the early 17th century.

feet of clay An unforeseen blemish in the character of a person hitherto held above reproach.

This expression originated with Daniel’s interpretation of Nebuchadnezzar’s dream in the Old Testament (Daniel 2:31-45). The Babylonian king had dreamed of an image completely made of precious metals, except for its feet, which were made of clay and iron. Daniel explained that the feet represented man’s vulnerability to weakness and destruction.

Homer sometimes nods An erudite way of saying, “Nobody’s perfect.” The expression is often used to indicate that an artistic performance or endeavor has fallen below expectations or has not been of consistently high quality. The phrase’s origin lies in lines from Horace’s De Arte Poética usually translated as: “I think it shame when the worthy Homer nods; but in so long a work it is allowable if drowsiness comes on.”

mote in the eye A fault or imperfection observed in a person by one who is guilty of something equally or more objectionable. This phrase comes from Matthew 7:3:

Mote refers to a small particle, as a bit of sawdust; beam refers to a glance, or eyebeam, formerly thought to be emitted from, rather than received by the eye. Shakespeare makes use of the allusion in Love’s Labor’s Lost:

An analogous proverbial exhortation is “People who live in glass houses shouldn’t throw stones.”

a rift in the lute A flaw or imperfection, particularly one that endangers the integrity of the whole; the one rotten apple that spoils the whole barrel. The expression, more familiar to British than American ears, comes from Alfred, Lord Tennyson’s Idylls of the King (1885):

rough edges Characteristics or manners indicating a lack of polish, refinement, or completion. Use of rough meaning ‘lacking in culture or refinement’ dates from at least the time of Shakespeare. It is difficult to pinpoint exactly when edges, probably originally referring to the edges of sawed lumber which have not been trimmed or sized, was added to make the new phrase. In current use, corners is a common variant of edges.