means The act of carrying out a task, role, or artistic work, or how well something or someone functions while doing so.

from From the Old French 'parfournir,' meaning to complete or carry out fully — 'par' (through, thoroughly) plus 'fournir' (to furnish, accomplish). It entered English as 'performen,' first about getting a thing properly done; the theatrical sense of acting before an audience grew later, fittingly making 'performance' a word that means both honest labor and pretending.