¹peculiar

characteristic, individual, peculiar, distinctive mean indicating a special quality or identity. characteristic applies to something that distinguishes or identifies a person or thing or class <responded with her characteristic wit>. individual stresses qualities that distinguish one from all other members of the same kind or class <a highly individual writing style>. peculiar applies to qualities possessed only by a particular individual or class or kind and stresses rarity or uniqueness <an eccentricity that is peculiar to the British>. distinctive indicates qualities distinguishing and uncommon and often superior or praiseworthy <a distinctive aura of grace and elegance>.

strange, singular, unique, peculiar, eccentric, erratic, odd, quaint, outlandish mean departing from what is ordinary, usual, or to be expected. strange stresses unfamiliarity and may apply to the foreign, the unnatural, the unaccountable <a journey filled with strange sights>. singular suggests individuality or puzzling strangeness <a singular feeling of impending disaster>. unique implies singularity and the fact of being without a known parallel <a career unique in the annals of science>. peculiar implies a marked distinctiveness <the peculiar status of America's first lady>. eccentric suggests a wide divergence from the usual or normal especially in behavior <the eccentric eating habits of preschoolers>. erratic stresses a capricious and unpredictable wandering or deviating <a friend's suddenly erratic behavior>. odd applies to a departure from the regular or expected <an odd sense of humor>. quaint suggests an old-fashioned but pleasant oddness <a quaint fishing village>. outlandish applies to what is uncouth, bizarre, or barbaric <outlandish fashions of the time>.

The word peculiar first meant “a person's own.” You may have some quality that is just your own. No one else has it. That surely makes it unusual. This is how peculiar came to mean “unusual” or “odd.”