Not drawing attention to oneself; modest. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "self-effacing" in a sentence
"Weingart stared straight ahead, his expression self-effacing, his hands resting on the spokes of his steering wheel."
"Lily is a rather private person and has been described as self-effacing."
"This rabbi is too self-effacing and that one— good God!"