It is a figure of speech in which a positive is stated by negating its opposite. Examples: A. She's not the brightest girl in the class. (She's stupid!) B. He's not the most handsome fellow! (he's...
No. A litotes ( notice the s there) is a figure of speech using a negated opposite to affirm something, for example "Being short and fat is no small problem for a prospective high-jumper."