IPA: /ˈraɪətəsli/
KK: /ˈraɪətəsli/
In a way that is very funny or causes a lot of laughter and excitement.
The comedian performed riotously, making everyone in the audience laugh out loud.
Riotously → It is formed from "riot" (from Old French *riote*, meaning a noisy quarrel or disturbance) and the suffix "-ously" (meaning in a manner characterized by). The word "riotously" means in a manner characterized by noisy and uncontrolled behavior or disturbance.
Think of a noisy quarrel ('riot') and how doing something 'in a manner characterized by' that noise ('-ously') means acting in a riotous way.