bodybuilder UK /ˈbɒ.diˌbɪl.də/US /ˈbɑ.diˌbɪl.dəɹ/ noun1 •A person who uses diet and exercise to build an aesthetically muscular physique, in order to compete in bodybuilding.In the competitions, bodybuilders go through "mandatories"—a set of mandatory poses—in the morning, where the judges compare the body parts of the builders. — 1991 formsbodybuilders