Uneducated means having had little or no schooling. A fact about opportunity, not about intelligence.
That distinction matters, because the word is often used as if it meant stupid, which is a different thing entirely, and a great many uneducated people have been extremely clever. Careful writing uses it about access to schooling rather than about a person's worth. There is a lighter use in an uneducated guess, meaning one made without knowledge, which plays against the phrase an educated guess.
1adjectiveuneducatedHaving had little or no formal schooling.
“Both his parents were entirely uneducated.”
From un- + educated.
Etymology from Wiktionary, CC BY-SA