Lexical Definition

‎προσκόπτω‎ proskóptō (pros-kop'-to) to strike ^G:V
from ‎πρός‎ and ‎κόπτω‎

beat upon, dash, stumble (at).

• to strike at, i.e. surge against (as water)
• specially, to stub on, i.e. trip up (literally or figuratively)

Abbott-Smith

προσ-κόπτω, [in LXX for נגף, כּשׁל ni., etc.;]
1. trans., to strike (e.g. hand or foot) against: c. acc. seq. πρός, fig., Mt 4:6, Lk 4:11(LXX).
2. Intrans., to stumble: absol. (To 11:9, Pr 3:23), Jo 11:9, 10; of wind, to rush against, beat upon: c. dat, Mt 7:27. Metaph., in late writers,
(a) to offend (Polyb.);
(b) to take offence at, stumble at: seq. ἐν, Ro 14:21; c. dat., τ. λόγῳ, I Pe 2:8; τ. λίθῳ τ. προσκόμματος, Ro 9:32.†

Abbott-Smith References

Liddell-Scott-Jones

προσκόπτω,

strike one thing against another, πρὸς λίθον τὸν πόδα [LXX+5th c.BC+]

__b intransitive, stumble or strike against, τινι [Refs 5th c.BC+]; π. τῷ ὀφθαλμῷ (i.e. ῥίζῃ κυάμου) [Refs 4th c.BC+]; of liquid, to be checked by striking against, with dative, [Refs 1st c.AD+]; πνεῦμα προσκόπτον broken, interrupted breathing, [Refs 5th c.BC+]
__2 π. τῷ ἄξονι encounter friction at.. , [Refs 4th c.BC+]
__II metaphorically, ={προσκρούω} [Refs]offend, [Refs 3rd c.BC+]; οὐ μόνον δυσαρεστήσειν ἀλλὰ καὶ προσκόπτειν ἔμελλε προφανῶς, of an open breach, [Refs]
__II.2 take offence at, ἵνα μή μοι προσκόψῃς [Refs 3rd c.BC+]; τῇ βαρύτητί τινος [Refs 4th c.BC+]; of things, π. τῷ ζῆν to be disgusted with life, [Refs] —passive, δῆμος π. αὐτῷ διά τι being offended with him, [Refs 1st c.BC+]

_{LSJ Scripture Refs: LXX.Ps.90.12*}