Give someone a hint about something, as in Janet put a bug in her husband's ear about getting the children a dog for Christmas. This idiom presumably likens the buzzing about of an insect to a hint, although the exact analogy is not clear. [c. 1900]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.