Where does “πανικός” come from?

πανικός (Ancient Greek) comes from Ancient Greek πᾶν, from Ancient Greek ὀπτικός, from Ancient Greek ὄψις, from Ancient Greek ὄψ, from Proto-Hellenic wókʷs, from Proto-Indo-European wekʷ- — to speak, to sound out.

πανικός (Ancient Greek): pertaining to Pan