- Not available on that edition (the reason is in the tooltip)
- Depends on the setting, your class or another addon (details in the tooltip)
What it does
Checks how the character stat you choose on the unit specified compares with the number you set. A unit that does not exist does not match.
Why you might use it
Compares a primary stat (Strength, Agility, Stamina, Intellect, Spirit) or Armor for a unit, usually you or your pet. Use it to react to temporary boosts, such as saving a big hit for when a trinket or enchant proc has raised your Strength, or to pick a safer rotation when your Armor is low. On Retail and WoW Forever the game can hide stats, and the condition is unavailable while it does. For secondary stats such as crit and haste, see Extended Character Stat.
Example
your Strength is greater than 600
Settings
What each setting in the condition editor means, from the game's own help.
Unit - The unit this condition uses as the target of comparison.
Character Stat - The character statistic you are interested in.
Operator - How to compare Character Stat with the Character Stat value. This comparison uses basic mathematical comparison operations.
Character Stat - The current value of the selected stat for Unit.