Kristin Cavallari's still very single ... despite that recent video of her getting flirty and kissing a comedian.
Sources close to the situation tell TMZ ... there's nothing serious going on between Kristin and Jeff Dye, and in fact -- we're told they've only hung out that one time they were seen in Chicago looking like a new couple.
Our sources say Kristin's just having fun right now and doesn't have -- nor is she looking for -- a boyfriend.
As for how Kristin and Jeff connected .