1925, "a crippled leg," also "a crippled person," perhaps by association with limp, or a corruption of gammy (see game (adj.)).
also gymp, ornamental material for trimming dresses, furniture, etc., 1660s, from French guimpe, Old French guimple "wimple, headdress, veil," from a Germanic source (cf. Old High German wimpal).
: The old guy was gimping across the street