Lexical Definition

‎κατασείω‎ kataseíō (kat-as-i'-o) to signal ^G:V
from ‎κατά‎ and ‎σείω‎

beckon.

• to sway downward, i.e. make a signal

Abbott-Smith

** κατα-σείω, [in LXX: Da TH Bel 14 AR, I Mac 6:38*;]
1. to shake down.
2. Of the hand, to shake or wave as a signal: τ. χεῖρα, Ac 19:33; τ. χειρί, Ac 13:16; id. c. dat. pers., Ac 21:40; seq. inf., Ac 12:17.†

Abbott-Smith References

Liddell-Scott-Jones

κατασείω-σείω,

future -σείσω [Refs 5th c.BC+]: perfect -σέσεικα [Refs 3rd c.BC+]:—shake down, throw down, [Refs 5th c.BC+]; τεῖχος, τοῦ τείχους ἐπὶ μέγα, [Refs 2nd c.AD+] —passive, fall down, [Refs 1st c.AD+]; of a lion's mane, [Refs 2nd c.AD+]: metaphorically, [Refs 4th c.BC+] until he laid him on the floor (with drinking), [Refs 4th c.BC+]

__2 impel, drive headlong, [Refs 4th c.BC+] —passive, πρὸς τὸ λέγειν κ. [Refs 4th c.BC+]
__3 in Surgery, treat by shaking, [Refs 5th c.BC+] —passive, [Refs]
__4 κατασείωσείσας τὴν χεῖρα with a motion of the hand, [NT+1st c.AD+]; κ. τὰ ἱμάτια, by way of signal, [Refs 1st c.AD+] beckon with the hand, [Refs 2nd c.BC+]: absolutely, κ. τινί beckon to another, as a sign for him to be silent, [Refs 5th c.BC+]; but also, shake the head in token of contempt, [Refs 1st c.BC+]

_{LSJ Scripture Refs: Acts.19.33}