expert vs efficiency expert

Other hyponyms of expert include ace, adept, champion, genius, hotshot, maven, mavin, sensation, star, superstar, virtuoso, whiz, whizz, wiz, wizard, agronomist, all-rounder, all arounder, analyst, analyst, anatomist, antiquarian, antiquary, archaist, arbiter, supreme authority, archer, bowman, authority, black belt, cabalist, kabbalist, calculator, computer, estimator, figurer, reckoner, climatologist, computer expert, computer guru, cosmetologist, efficiency engineer, exegete, genealogist, geographer, horticulturist, plantsman, investigator, jurist, legal expert, lapidarist, lapidary, logician, logistician, mnemonist, mythologist, nerd, commentator, observer, out-and-outer, parliamentarian, past master, prosthetist, pteridologist, guide, pathfinder, scout, shark, shooter, shot, specialiser, specialist, specializer, talent, technician, technocrat, healer, therapist, old-timer, old hand, old stager, oldtimer, stager, veteran, warhorse.