mid-14c., "a false show, false profession," from Old French simulation "pretence" and directly from Latin simulationem (nominative simulatio) "an imitating, feigning, false show, hypocrisy," noun of action from past participle stem of simulare "imitate," from stem of similis "like, resembling, of the same kind" (see similar). Meaning "a model or mock-up for purposes of experiment or training" is from 1954.