Stand/stick out a mile
Definition 1 of 1
Pro Tip 1/3Negative Nuance
This phrase often implies something negative or unwanted is very obvious. 
His disapproval stood out a mile during the meeting.
Pro Tip 2/3Exaggerated Visibility
Used to emphasize that something is extremely easy to notice or recognize. 
The typo in the headline stuck out a mile.
Pro Tip 3/3No Hiding
Implies that the thing being noticed cannot be concealed. 
His mismatched socks stuck out a mile; there was no hiding them.