Wiktionary
dim bulb
alt. (context idiomatic English) A person who is slow-witted. n. (context idiomatic English) A person who is slow-witted.
Usage examples of "dim bulb".
In a room with scuffed floors and an old rocker and a single dim bulb hanging down, it appeared to him that a stopped clock was more or less appropriate.
The plumbing was pre-World War II, the lighting was a single dim bulb hanging from the ceiling, and the carcass of an enormous cockroach lay on its back in the corner, but she wasn't in the mood to quibble.
We all gathered at the bottom of the stairs as Steve reached out and pulled the chain that lit the single dim bulb hanging from the rough wooden beams above our heads.
The last dim bulb of reason in his brain showed him Silence and Circumspection, and then went out.