Orion's text has erroneously λούπτω instead of λάπτω. Philoxenus' etymology cannot be understood if we separate from the etymology of λαῖλαψ "furious storm", fr. 536: λαῖλαψ· παρὰ τὸ λάπτω, ὁ μέλλων λάψω, καὶ ἀποβολῇ τοῦ ω λάψ, ὡς φυλάξω φύλαξ, ἑλίξω ἕλιξ, καὶ κατὰ ἀναδιπλασιασμὸν λάλαψ, μετὰ προσθέσεως τοῦ ι λαῖλαψ. δηλοῖ δὲ τὴν λίαν {καὶ} σφοδρὰν καὶ ἐπιτεταμένην λαβρότητα τοῦ πνεύματος "lailaps "furious storm" comes from laptō "to drink eagerly", the future is lapsō, and by dropping of the [ō], laps, as in phulaxō "I will keep", phulax "guard", helixō "I will twist", helix "twisting"; by reduplication, *lalaps, and adjunction of the [i], lailaps. It means the extreme and intense violence of the wind" (see λαῖλαψ / λάπτω) Thus, λαβρός being an epithet of the wind and λαίλαψ a windstorm, the two were etymologized together. The verb λάπτω was etymologized as a compound of the intensive λα- and ἅπτω "to touch" (Orion, Etymologicum, lambda, p. 96, probably going back to Philoxenus although it is not in Theodoridis: Λάπτω. παρὰ τὸ λα μόριον ἐπίτασιν δηλοῦν, ὡς καὶ τὸ αρι, καὶ τὸ ερι, καὶ τὸ ζα. τὰ λάπτω οὖν δηλοῖ τὸ λίαν ἅπτεσθαι. λάπτοντες, οἷον προσκείμενοι τῷ ὕδατι) (see λάπτω / λα- + ἅπτω). Arguably, a windstorm "touches violently", and so does the λάβρος "violent" wind. And "to drink eagerly" was to "touch impetuously" water. From a formal point of view, deriving λάβρος from λάπτω implies a change of voiceless [p] into voiced [b].