means To carry out an action, task, or piece of art — especially in front of others, where the result actually counts.

from From Old French 'parfornir,' to complete or accomplish fully, built from 'par-' (through, thoroughly) and 'fornir' (to provide, furnish — a cousin of our 'furnish'). So at root, to perform is to thoroughly furnish a thing into being. English borrowed it in the medieval period as 'performen,' and the spelling drifted toward 'form,' as if the word were quietly insisting that performing means giving something its full shape.