word of mouth

informal oral communication: The rumor spread rapidly by word of mouth.

RELATED WORDS

First recorded in 1545–55

word-of-mouth, adjective

But word-of-mouth and changing times soon made it a classic.
The Catch in “Catch-22”|Morris Dickstein|September 4, 2011|DAILY BEAST
Through databases and word-of-mouth, everyone was fairly aware of who they were working with.
Porn’s New HIV Problem|Richard Abowitz|September 2, 2011|DAILY BEAST
Word-of-mouth should be strong and this movie is likely to have what the industry calls “legs.”
Is Star Trek Now Cool?|Kim Masters|May 7, 2009|DAILY BEAST
But it was by word-of-mouth invitation that I was in her kitchen yesterday morning.
The Little Lady of the Big House|Jack London

You might hear the warning given on radio or television, or even by word-of-mouth.
In Time Of Emergency|Department of Defense
Word-of-mouth publicity accounts for the gradual steady growth in the use of the rooms.
The Library and Society|Various
Bn Shaikh is well-apprized of word-of-mouth matters, and will inform thee of them.
The Bbur-nma in English|Babur, Emperor of Hindustan
This will be an unceremonious summary of a word-of-mouth message.
The Bbur-nma in English|Babur, Emperor of Hindustan