Where does “double-jointed” come from?

double-jointed (English) comes from English jointed, from English joint, from Middle English upon, from Middle English up-, from Old English ūp-, from Old English ūp, from Proto-Germanic upp, from Proto-Germanic ub.

double-jointed (English): Having one or more joints (usually those of the fingers, arms, or legs) able to bend more than is normal; possessing hypermobility of one or more joints

Definitions

  1. Having one or more joints (usually those of the fingers, arms, or legs) able to bend more than is normal; possessing hypermobility of one or more joints

Ancestry of “double-jointed”, step by step

double-jointed traces back through two separate lines of ancestry.

via English jointed

StepLanguageWordMeaning
1EnglishjointedHaving joints; Extremely full of people, packed,...
2EnglishjointDone by two or more people or organisations...
3Middle Englishuponupon
4Middle Englishup-
5Old Englishūp-up-
6Old Englishūpup, from above
7Proto-Germanicuppup, upwards
8Proto-Germanicubunder
9Proto-Indo-Europeanupóunder, below
10Proto-Indo-Europeanh₃ewp-

via English doublé

StepLanguageWordMeaning
1EnglishdoubléA compound attack that deceives the opponent's...
2Frenchdoublédouble, brace, pair; double; doublé
3Middle Frenchdouble
4Old Frenchdobledouble
5Latindūplusdouble (twice as much, or as big)
6Proto-Italic*duplosdouble

Words derived from “double-jointed

Every word from Proto-Indo-European h₃ewp-
double-jointed — Etymology, Origin & Word History | Etymology Explorer