Simple RAW 3

[Arkhios]

Q156 the only way you can disarm someone is if you're a fighter, right?

A156 Dungeon Master's Guide introduced a number of Action options which a DM may add as a group or individually into their game.

One of them is Disarm:

DISARM
A creature can use a weapon attack to knock a weapon or another item from a target's grasp. The attacker makes an attack roll contested by the target's Strength (Athletics) check or Dexterity (Acrobatics) check. If the attacker wins the contest, the attack causes no damage or other ill effect, but the defender drops the item. The attacker has disadvantage on its attack roll if the target is holding the item with two or more hands. The target has advantage on its ability check if it is larger than the attacking creature, or disadvantage if it is smaller.