Meaning

noun a person who is uninterested in intellectual pursuits

adjective characteristic of a person who is not cultivated or does not have intellectual tastes

originA bahuvrihi compound of low + brow. An Americanism whose first use appears c. 1902. Refers to the (by that time discredited) pseudoscience of phrenology, which suggested that a person of low intelligence and sophistication would possess a lower brow-line than someone of greater intelligence and sophistication.

Etymology from Wiktionary, CC BY-SA 3.0