Origin and history of junkie

mid-14c., junke "old cable or rope," cut in bits and used for caulking, etc., a nautical word of uncertain origin, perhaps from Old French junc "rush, reed," also used figuratively as a type of something of little value, from Latin iuncus "rush, reed" (but OED finds "no evidence of connexion").

It was extended to "old refuse from boats and ships" (1660s), then to "old or discarded articles of any kind" (1884), usually with a suggestion of reusability. Meaning "salt meat used on long voyages" is from 1762. Meaning "narcotic drug" is from 1925. Junk food is from 1971; junk art is from 1961; junk mail first attested 1954; junk bond from 1979.

diminutive suffix used in forming in pet proper names (Christy, Sandy, Jemmy), attested by c. 1400 in Scottish (as -ie). Perhaps it is a merging of the common adjective ending -y (2) with old fem. suffixes in -ie. It might have been reinforced by Dutch -je in similar use.

According to OED (1989) it became frequent in English 15c.-16c.

The use with common nouns, childish names of animals (Jenny wren), etc., also seems to have begun in Scottish (laddie is by 1540s) and become popular in English from late 18c. via Burns (timrous beastie). But the formation perhaps appears earlier in baby and puppy, and compare hobby in hobby-horse. Granny, dearie, and sweetie all are 17c. and early 18c.

In general use with names of girls (Kitty, Jenny), where it coincides with names such as Mary, Lucy, Lily, where it is not a diminutive. The extension to surnames seems to be from c. 1940.