gammy

[gam-ee] /ˈgæm i/
adjective, gammier, gammiest. British Informal.
1.
disabled; lame:
a gammy leg.
Origin
1830-40; orig. dial., perhaps < dialectal French; compare Normandy dial. gambier having bad legs, gambie lame, Middle French gambi bent, crooked, all ultimately derivative of Late Latin gamba; see jamb1
British Dictionary definitions for gammy

gammy

/ˈɡæmɪ/
adjective -mier, -miest
1.
(Brit, slang) (esp of the leg) malfunctioning, injured, or lame; game US equivalent gimpy
Word Origin
C19: from Shelta gyamyath bad, altered form of Irish cam crooked; see game²