Phrynichus Arabius (/ˈfrɪnɪkəs/; Ancient Greek: Φρύνιχος Ἀράβιος, lit.
'Phrynichus “the Arab”')[1][2] or Phrynichus of Bithynia (Ancient Greek: Φρύνιχος ὁ Βιθυνός) was a grammarian of the Greek language who flourished in 2nd century Bithynia, writing works on proper Attic usage.
It is dedicated to Cornelianus, a man of literary tastes, and one of the imperial secretaries, who had invited the author to undertake the work; it is a collection of current words and forms which deviated from the Old Attic standard, the true Attic equivalents being given side by side.
The work is thus a prescriptive and reforming lexicon antibarbarum, and is interesting as illustrating the changes through which the Greek language had passed between the 4th century B.C.
and the 2nd century A.D.[6] As models of Attic style Phrynichus assigns the highest place to Plato, Demosthenes, and Aeschines the Socratic,[6] and also uses the other Attic orators, Thucydides, Sophocles, Aeschylus, and Euripides, though he does not accept their usage uncritically: in the letter to Cornelianus which forms the introduction to the Eclogē, he criticizes some words used by classical Attic authors as un-Attic "mistakes" (Ancient Greek: διημαρτημένα).