動詞 wigwag:

1. send a signal by waving a flag or a light according to a certain code
2. signal by or as if by a flag or light waved according to a code

wig.wag

v.（動詞）
wig.wagged,wig.wag.ging,wig.wags
v.intr.（不及物動詞）
To move back and forth; wag steadily or rhythmically:
搖動，搖擺：前后移動；穩(wěn)定而有節(jié)奏地搖擺：
例句：
watched the pendulum wigwag.
觀察鐘擺的擺動

To signal by waving an upraised arm, a flag, or a light, especially in accordance with a code.
打旗語，用燈光發(fā)信號：通過搖動舉起的手臂、旗子或燈來示意，尤指按符號示意
v.tr.（及物動詞）
To move (something) back and forth steadily or rhythmically.
搖動：前后穩(wěn)定而有節(jié)奏地移動（某物）
To convey (a message or signal) by waving an upraised arm, a flag, or a light.
打旗語發(fā)信號，用燈光發(fā)信號：通過搖擺舉起的手臂、旗子或燈來傳達（信息或記號）
n.（名詞）
The act or practice of wigwagging.
搖動，搖擺：搖擺的動作或作法
A message sent by this method.
旗語信號，燈光信號：通過旗語、燈語或手勢傳達的消息

來源：
Dialectal wig [to move]
方言 wig [移動]
wag
wag

【引伸】
wig.wag.ger
n.（名詞）