17th cent. Old Spanish xefe. From French chef, from Vulgar Latin *capum, from Latin caput "head" (see cabo).
The -e ending was originally neuter and then re-analyzed as masculine. Thus modern feminine forms are split between la jefe and la jefa. Jefa is first attested in the 19th cent.
Romance: Western Vulgar Latin: Asturian cabu, Portuguese cabo, Galician cabo, Catalan cap, French chef, Italian capo; Eastern Vulgar Latin: Aromanian cap, Romanian cap