twen·ty–twen·ty or 20/20 
/ˈtwɛntiˈtwɛnti/ adjective
/ˈtwɛntiˈtwɛnti/ adjective : having good vision and able to see without glasses
▪ My mother has 20/20 vision.
▪ My mother has 20/20 vision.
twenty-twenty hindsight or 20/20 hindsight
: the full knowledge and complete understanding that you have about an event only after it has happened
▪ With 20/20 hindsight we now see where our strategy went wrong.
▪ With 20/20 hindsight we now see where our strategy went wrong.
