Better untaught than ill taught
Possible interpretation: This proverb drops the verb "to be" (It is better to be untaught than ill taught). We understand: "It is better not to be taught at all than to be taught badly." It's better not to learn something than to learn it badly.Note: taught = past participle of verb "teach" (here used in passive voice) | ill taught = badly taught
This idea is echoed in Pope's famous line: "A little Learning is a dang'rous Thing"