The idea is one of doing something such that the subject of the verb looks or behaves like something (or someone) else or represents something (or someone) else. The word has no connotation of fraud or anything underhanded (in this respect, it's like ghet). The object is the thing being simulated or the person being impersonated. lIlwI' (simulator, for lack of a better term) is different from lIw (substitute) since lIw implies replacement (the notion of instead of) while a lIlwI' doesn't replace anyone or anything.