Main Entry: 1sim·ple
Pronunciation: \ˈsim-pəl\
Function: adjective Inflected Form(s): sim·pler \-p(ə-)lər\ ;
sim·plest \-p(ə-)ləst\
Etymology: Middle English, from Anglo-French, from Medieval Latin simplus, alteration of Latin simplic-, simplex single, having one ingredient, plain, from sem-, sim- one + -plic-, -plex -fold — more at same, -fold
Date: 13th century
Merriam-Webster
Lighten up, Francis.
You've never seen "simple" used as a noun? Is English your first language?
It's not a matter of me "lightening up," it's more of a matter of usage. I'll sit here all day and teach.