Make a persistent effort regarding; also, persistently urge someone to do something. For example, We'll have to keep after the cobwebs, or He won't get anything done unless you keep after him. Also see keep at, def. 2.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.