These words all denote an aspect or peculiarity of a person’s character or manner. Eccentricity is used to identify a characteristic, action, practice or habit that differs in some way from what is usual or expected; the word suggests a strangeness or irregularity that may be harmless but that is an ingrained part of the personality.

• Smoking cigars was part of the old lady’s eccentricity ; One of his eccentricities was a stubborn reluctance to entrust his savings to a bank.

By contrast, quirk is the most general of this group and suggests little as to the nature or the trait involved; quirks can be pleasant or unpleasant, amusing or irritating: Knuckle-cracking was his most annoying quirk . The word originally referred to a kind of verbal trick or conceit. Bright retorts, plays on words, subtle evasions, all were described as quirks . Although the term can be and still is used in this way, it more often now designates a distinctive trait of behaviour rather than of speech. In any case, the word can suggest a slight slip, flaw or distortion: a keen mind, but one full of quirks . Idiosyncrasies are like eccentricities in that they are strange in nature, but the word implies less a divergence from the general than an emphasis on the individual. Eccentricities are often an indication of mental aberration, idiosyncrasies the evidence of a strongly independent personality: His refusal to wear a tie at work in the summer is one of my uncle’s most admirable idiosyncrasies . Oddity is interchangeable with eccentricity because of its suggestion of the aberrant and peculiar. However, the word is more often used to designate an odd or unique person or thing than a quality or trait.

• What a collection of oddities he invited to his party!; A bargain is an oddity in that store; all their merchandise is overpriced.