Definition

The adjectival form of "sus" (suspicious), used to describe anyone or anything giving off sketchy, untrustworthy, or decidedly questionable vibes that set off your internal alarm.

Example Usage

That guy asking to borrow money five minutes after meeting him is giving off major sussy energy.

Source: Urban Dictionary (https://www.urbandictionary.com/define.php?term=sussy&defid=17317774)