Is Expelliarmus a disarming spell or a spell 2 pop your wand out of your hand?

Expelliarmus "produces a jet of scarlet light. This spell is used to disarm another wizard, typically por causing the victim's wand to fly out of reach. It can also throw the target backwards when enough power is put into it. If it hits, or gets close, to another spell, if powerful enough, it will deflect the spell, causing it to hit its caster. As demonstrated in Prisoner of Azkaban, simultaneous use of this spell por multiple witches or wizards on a single person can throw the wizard back with much greater force."

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I'm confused, that's the same thing isn't it? If it pops the wand out of the opponents hand, then you have disarmed them...

they make the wand shoot out of their hand, BUT if they put enough power on the spell, the wizard will indeed be thorn backwards