dim bulb

noun

1. informal.
   a slow-witted unintelligent person

Example Sentences

Despite its proximity, it’s a dim bulb that is so faint that it demands a decent telescope to be seen at all.

From Scientific American

So it is understandable that Rivera in particular would embrace the glow that comes with a win that, upon further examination, might be a dim bulb.

From Washington Times

The pensive basketball coach Steve Kerr makes an appearance, as does the cartoonist Gary Trudeau and the biologist Richard Dawkins, as well as a smattering of Nobel Prize winners, MacArthur “genius grant” recipients and other bright lights bound to make you feel like a dim bulb.

From Washington Post

By the third step, I could reach out my right arm and find the switch to a dim bulb that would illuminate my happy place: a magical culinary kingdom filled with rows of fermented vegetables, preserved fruits, radiant bottles of golden sunflower oil, and jugs of grandma’s homemade wine that she, my babusia, is so proud of.

From Washington Post

Alan is a sweet, dim bulb who wants to be Dash, and Tatum's entrance at a book event where he performs a "Magic Mike" routine is amusing.

From Salon