History:
The expression was first noticed in the 1920's, and it's first publication was in the February 1922 edition of the Oakland Tribune. Came into wide acceptance during The 1960's,
Meaning:
To be a "fly on the wall," means being able to see and hear what is happening around you without being noticed. This reflects the fact that a fly on the wall generally goes unnoticed while activity proceeds around it.
Example:
When my husband and I finally admitted that we were officially dating, after finding each other mutually attractive for some time, our friend Ray expressed that he'd have liked to have been a fly on the wall when that took place! Sorry, but some things are private!
