Garry's Mod Wiki

IsEntity

You might be looking for isentity, which has the same name, but is lowercase and not deprecated.
  boolean IsEntity( any variable )

Description

We advise against using this. It may be changed or removed in a future update. Use the function isentity instead.

Identical to isentity. Returns if the passed object is an Entity.

Arguments

1 any variable
The variable to check.

Returns

1 boolean
True if the variable is an Entity.