An overly exaggerated frown made in response to anything particularly stupid seen anywhere, be it an action, a behavior, the weather, some music, etc.
Anybody employing a fail frown must be aware that they must, to the best of their abilities, follow the guiding scientific principle principle-every action has an equal and opposite reaction.
This actually happened to me, so please, read it in order to contextualize this compound word. In essence, it was a message about corporate buzzwords and euphemisms I had sent to a friend.
-I talked to a woman this morning who is the owner of a cafe. She told me she used to be a paraprofessional, which is basically a glorified teacher´s assistant. She likened the euphemism to a custodian being named a "custodial manager." We both made a "fail frown" after she had finished explaining it to me.