Which word is best defined as 'widely learned'?

The term 'erudite' is best defined as 'widely learned' because it specifically refers to a person who has acquired extensive knowledge through reading and study. An erudite individual is not just knowledgeable in a superficial sense; they possess a deep understanding of a wide range of subjects, often reflecting a scholarly approach to learning. This sets it apart from the other options.

'Knowledgeable' generally refers to someone who has information or facts about various topics, but it does not necessarily imply the depth or extensive breadth of knowledge that 'erudite' conveys.

'Intelligent' refers more to a person's ability to think, reason, and understand complex ideas rather than the breadth of their learned knowledge.

'Astute' implies sharpness in judgment, perception, or insight, often in practical or strategic matters, rather than a focus on acquired knowledge through study.

Therefore, 'erudite' is the most precise term to denote someone who is widely learned across various fields.