FLAZE ORIGINS

Somebody, I assume from my school, just requested the word flaze. This is a slang term which means something like "ridiculous" or "terrible". A quick Internet search yielded absolutely no results on this except some Urban Dictionary entry defining it as "something you don't like". No origin listed there, or anywhere else for that matter. However, when I was recently reading Elizabeth Cady Stanton's Declaration of Sentiments, I noticed she used the phrase "flase supposition". This has a very similar context and I was in fact able to get a definition on it: apparently it's an old word meaning "weak". However, it's still too obscure for an etymology. Based off its monosyllabacy and fl- initial sound, this probably has ancient Germanic origins. This is all conjecture, however, so take my ramblings with a grain of salt.