guy 1: i have a thing for this girl guy 2: so that's what you've been up to the last 3 weeks
"a thing is when 2 people like each other, and they're "seeing each other" and no one else
"guy 1: i have a thing for this girl guy 2: so that's what you've been up to the last 3 weeks" What is the definition of "a thing"?