separation anxiety

noun
  1. the normal fear and apprehension expressed by infants when removed from their mothers or approached by strangers.
  2. any similar reaction in later life caused by separation from familiar surroundings or close friends or family.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for separation anxiety

separation anxiety

noun
  1. psychoanal a state of distress felt at the prospect of being separated from a familiar or beloved person
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

separation anxiety in Medicine

separation anxiety

[sĕp′ə-rāshən]
n.
  1. A child's apprehension or fear associated with his or her separation from a parent or other significant person.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.