Zizoo, there are plenty of mismatched (i.e. Greek + Latin elements) words that have been established in contemporary English (e.g. hypersensitive), so hypoflexive has lots of company, however scruffy such company might seem to etymology mavens like me (and, I presume, Qroqqa). If you want to be consistent (though some hold that consistency is the hobgoblin of little minds, of course), you could use the Latin prefix sub-, which would give you (I think) sufflexive. Or you could search out the Greek root for "bend" (Qroqqa could help, I bet).
Zizoo, you don't really have to delete a word only because it has mixed etymology, or a fake one. 99% of Urban Dictionary users doesn't even try to justify their entries, and yours are much nicer, I.M.H.O.
qroqqa was just correcting your comment, because there's something incorrect!