"Not too bad" for "very good"

• Figure of speech like "no mean feat"
• Little child in stories making understatement
• Ironical understatement
• Figure of speech like "not unlike"
• using ___: “Mary had no giant lamb / Its fleece was not unwhite”
• Understatement for rhetorical effect (especially when expressing an affirmative by negating its contrary)

WordNet Word definitions in WordNet
n. understatement for rhetorical effect (especially when expressing an affirmative by negating its contrary); "saying `I was not a little upset' when you mean `I was very upset' is an example of litotes" [syn: meiosis ]

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Meiosis \Mei*o"sis\ (m[-i]*[=o]"s[i^]s), n. [NL., fr. Gr. mei`wsis, fr. meioy^n to make smaller, from mei`wn. See Meionite .] (Rhet.) Diminution; a species of hyperbole, representing a thing as being less than it really is; understatement; see also litotes ...

Wiktionary Word definitions in Wiktionary
n. (context rhetoric English) A figure of speech in which the speaker emphasizes the magnitude of a statement by denying its opposite; a figure of speech in which understatement is used with negation to express a positive attribute; a form of irony