flag (someone) down

Translations
остановить (кого-то), помахав рукой
He flagged down a taxi in the busy street.
Он остановил такси, помахав рукой, на оживленной улице.
Definitions
To signal to a person, typically a driver or a passerby, to stop or come over, often by waving or using a hand gesture.
Words
flag

verb
останавливать
someone

pronoun
кого-либо
down

adverb
жестом