expression
from the side; from one's side
Describes physical direction or position: something comes from the side, or someone approaches from the side.
車が横から飛び出してきた。
A car suddenly came out from the side.
彼は横からそっと近づいた。
He quietly approached from the side.
expression
from an outsider; from an uninvolved person
Used when someone not directly involved in a matter interjects or interferes. Often appears in the set phrase 横から口を挟む (to cut in from the side).
See also: 横から口を挟む
会議中、横から口を挟まないでください。
Please don't cut in from the side during the meeting.
横から余計なことを言うな。
Don't say unnecessary things from the sidelines.