tubelight

Etymology
. The "dim-witted person" sense arises from their flickering as well as the length of time it takes for one to light up completely after being switched on.

Noun

 * 1)  A fluorescent lighting tube.
 * 2)  a dim-witted person; someone who is slow to understand or reply.
 * 1)  a dim-witted person; someone who is slow to understand or reply.
 * 1)  a dim-witted person; someone who is slow to understand or reply.