Definition

The ultra-lazy text abbreviation for 'busy right now sorry,' deployed by people too overwhelmed or uninterested to type out a full response—the digital equivalent of a rain check.

Example Usage

You: 'Wanna hang out?' Your friend: 'BRNS mate, swamped at work'

Source: Urban Dictionary (https://www.urbandictionary.com/define.php?term=BRNS&defid=10854073)