IPA: /vɛkˈseɪʃəsli/
KK: /vɛkˈseɪʃəsli/
In a way that causes annoyance or frustration.
The constant interruptions vexatiously disrupted the meeting.
Vexatiously → It is formed from "vexare" (meaning to trouble or annoy) and the suffix "-ious" (meaning full of). The word "vexatiously" means in a manner that is full of trouble or annoyance.
Think of someone who is 'troubling' ('vexare') others 'full of' annoyance ('-ious') — that's why vexatiously means doing something in a troublesome way.