get the nod
Receive approval or assent, as in, The contestant got the nod from the judges. Similarly give the nod means “to show approval or assent.” These expressions allude to the quick inclination of the head to indicate approval. [First half of 1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.