Ferti is a definition of a guy who is somewhat of a wizard in the real world: his skills include releasing unbelievable amounts of words only to be followed by awkward silence in which the audience is not certain of what just happened.
The word Ferti can be used a slang for the philosophical paradigm of the tree in the forest and whether it makes a sound if no one's around to hear it.
Ferti is also a guy usually married to Vaya.
'That guy's such a Ferti, I think my ears are bleeding.'
'Would that Ferti talk as much if there was no one around to hear him?'