1. To do something rebelliously; often disobeying authority or some other source of external social pressure.
2. Common mis-spelling of definitely, often arrived at when a person types definatly or definately into a spell-checker, and the spell-ckecher changes it to "defiantly".
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.
We have a Zoom meeting in a few minutes and I’ll probably go pajama casual.