ἀερολόγος

From LSJ

μήτε δίκην δικάσῃς πρίν ἀμφοῖν μῦθον ἀκούσῃς → do not give your judgement until you have heard a speech on both sides

Source

Spanish (DGE)

-ον
que habla en el vacío, charlatán anón. en PP 38.1983.13.