shrug one's shoulders - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Show indecision or indifference, as in When I asked her if she minded staying home, she just shrugged her shoulders. This redundant idiom—shrug means “to raise and contract the shoulders”—dates from about 1450.