Lexical Definition

‎δύσκολος‎ dýskolos (doo'-kol-os) difficult ^G:A
from ‎δυσ-‎ and (food)

hard.

• properly, fastidious about eating (peevish), i.e. (genitive case) impracticable

Abbott-Smith

δύσκολος, -ον (< κόλον, food), [in LXX for אֵיד, Je 29:9* (Je 49:8*) (of. δυσκολία, Jb 34:30; εὔκολος, II Ki 15:3) * ;]
1. properly, of persons, hard to satisfy with food, hence, generally, hard to please (Eur., Plat.).
2. Of things, difficult, hard (Arist.): Mk 10:24.†

Abbott-Smith References

Liddell-Scott-Jones

δύσκολος-κολος, ον,

(κόλον):

__I of persons, properly hard to satisfy with food [Refs 2nd c.AD+]: but, generally, hard to please, discontented, fretful, peevish, [Refs 5th c.BC+]; of animals, intractable, [Refs] adverb δυσκόλως, ἔχειν, διακεῖσθαι πρός τινα[Refs 5th c.BC+]
__II of things, troublesome, harassing, δ. ἡ ἡνιόχησις [Refs 5th c.BC+]: generally, unpleasant, ἄν τι δ. συμβῇ [Refs 4th c.BC+]; καιροὶ δ. difficult times, [Refs]. adverb -λως, ὑπακούειν [Refs 5th c.BC+]
__II.2 difficult to explain, [Refs 4th c.BC+]; δ. ἐστι it is difficult, [NT+1st c.AD+]; τὰ μὲν ῥάδια.. τὰ δὲ δ. [Refs 1st c.BC+]. adverb -λως hardly, with difficulty, [NT]

_{LSJ Scripture Refs: Mark.10.24 ☩ Mark.10.23}