prelapsarian \pree-laep-SEr-ee-ehn\ (adjective) - Characteristic of or belonging to the time or state before the fall of mankind.
"A five minute walk brought Jamie to a prelapsarian spot so pristine and undisturbed it struck her that Adam and Eve might have just abandoned it."
The invention of this word is relatively recent. Its first attested use was in 1879. Its etymology is transparent since its parts come from words and affixes that are familiar to everyone. Pre- "before" + lapse (from Latin lapsare "to slip, stumble, fall" + -arian, based on the suffixes -ary + -an, also found in "humanitarian," "necessitarian," "utilitarian," etc. If Noah lived before the flood, we say that he was "antediluvian" so, if Adam and Eve lived before the fall, we can as easily say they were "prelapsarian."