Idioms and Phrases with do one's homework
do one's homework
Be well prepared, as in Steve had done his homework before the meeting and could answer all of the client's questions. This usage transfers a school assignment to a broader context. [c. 1930]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.