lacid
A know-it-all who talks too much and never does anything. They’re like a smart kid who never finishes their homework and still acts like they’re the teacher.
My dad’s the lacid of the family. He says he knows everything but still can’t fix the Wi-Fi.
She’s so lacid, she explained the moon landing to my dog.
He’s the lacid of the group chat. He’s always right, but he never helps.