1660s, "the skin of a mole, used as fur," from mole (n.2) + skin (n.). From 1803 as the name of a kind of extra strong fustian.
Entries linking to moleskin
mole n.2
type of small burrowing insectivorous mammal (genus Talpa), mid-14c., molle (early 13c. in surnames); perhaps a shortening of obsolete moldwarp, literally "earth-thrower," but this sort of abbreviation is rare at that early age, and perhaps it is rather directly from the root of mold (n.3) "loose earth." It may represent an unrecorded Old English word; compare Middle Dutch mol, molle, Middle Low German mol, mul.
From c. 1600 as a figure of "one who works in darkness" (in Middle English, moldewerpe was figurative of a cleric overly concerned with worldly things). The espionage sense of "secret agent who gradually attains a position deep within organization or nation" was popularized 1974 in John le Carré (but suggested from early 20c.), from the notion of "burrowing."
skin n.
c. 1200, "animal hide" (usually dressed and tanned), from Old Norse skinn "animal hide, fur," from Proto-Germanic *skinth- (source also of rare Old English scinn, Old High German scinten, German schinden "to flay, skin;" German dialectal schind "skin of a fruit," Flemish schinde "bark"), from PIE *sken- "to peel off, flay" (source also of Breton scant "scale of a fish," Irish scainim "I tear, I burst"), extended form of root *sek- "to cut."
The usual Anglo-Saxon word is hide (n.1). The meaning "epidermis of a living animal or person" is attested from early 14c.; extended to fruits, vegetables, etc. late 14c. Jazz slang sense of "drum" is from 1927. As short for skinhead from 1970. As an adjective, it formerly had a slang sense of "cheating" (1868, compare the verb); that of "pornographic" is attested from 1968. Skin deep "superficial, not deeper than the thickness of the skin" (also literally, of wounds, etc.) is attested by 1610s:
All the carnall beauty of my wife, Is but skin-deep.
[Sir Thomas Overbury, "A Wife," 1613; the poem was a main motive for his murder]
The skin of one's teeth as the narrowest of margins is attested from 1550s in the Geneva Bible, a literal translation of the Hebrew text in Job xix.20. To get under (someone's) skin "annoy" is from 1896. Skin graft is from 1871. Skin merchant "recruiting officer" is from 1792 (the older sense is "dealer in hides"). Skin and bone as a description of emaciation or extreme leanness is in Middle English:
Ful of fleissche Y was to fele, Now ... Me is lefte But skyn & boon. [hymn, c. 1430]