ἀρνητής

From LSJ

πέτρην κοιλαίνει ρανὶς ὕδατος ἐνδελεχείῃ → constant dropping wears away a stone, constant dripping will wear away the hardest stone, little strokes fell big oaks, constant dripping wears the stone, constant dropping wears the stone, constant dripping will wear away a stone

Source

Spanish (DGE)

-οῦ
falsario, falaz Aq.Is.30.9, del Anticristo, 1Apoc.6
lat. negator, infitiator, Gloss.2.245.