Lexical Definition

‎σκυθρωπός‎ skythrōpós (skoo-thro-pos') sad ^G:A
from (sullen) and a derivative of ‎ὀπτάνομαι‎

of a sad countenance.

• angry-visaged, i.e. gloomy or affecting a mournful appearance

Abbott-Smith

σκυθρωπός, -όν (also -ή, -όν) (< σκυθρός, sullen, + ὤψ), [in LXX: Ge 40:7 (רַע), etc. ;]
of a gloomy countenance: Mt 6:16, Lk 24:17.†

Abbott-Smith References

Liddell-Scott-Jones

σκυθρωπός-ός, όν,

also ή, όν [Refs 5th c.BC+]: (σκυθρός, ὤψ):— of sad or angry countenance, sullen, [Refs 5th c.BC+]; also of affected gravity, [σκυθρωπόςότης}, 5th c.BC: Euripides Tragicus “Alcestis” 797, compare 5th-6th c.BC: Plato Philosophus “Symposium” 206d ">Refs 5th c.BC+]. adverb, -πῶς ἔχειν [Refs 5th c.BC+] with greater severity, [Refs 1st c.AD+]

__II of things, gloomy, sad, melancholy, γῆρας [Refs 5th c.BC+]; μέλη [Refs 1st c.AD+]
__II.2 of colour, sad-coloured, dark and dull, of the river Μέλας, [Refs 4th c.AD+]; of wine,[Refs]