Which word refers to evasion in words or speech; a roundabout expression?

The term that describes evasion in words or speech, especially through a roundabout expression, is circumlocution. This word originates from the Latin "circum" (around) and "locutio" (speech), illustrating the idea of speaking around a subject rather than addressing it directly. Circumlocution often involves using more words than necessary or speaking in a more complex manner to avoid getting straight to the point or to evade a direct answer.

By choosing this word, you capture the essence of indirect communication, where the speaker may aim to obscure the truth or avoid committing to a definitive statement. This contrasts with the other terms, which, while related to communication, do not specifically embody the concept of using roundabout expressions. For instance, prevarication implies a deliberate deviation from the truth but does not specifically indicate a roundabout way of speaking, while ambiguity refers to uncertainty or vagueness in meaning rather than the act of evasion itself.