In rhetoric

Rhetoric

Rhetoric is the art of discourse, an art that aims to improve the facility of speakers or writers who attempt to inform, persuade, or motivate particular audiences in specific situations. As a subject of formal study and a productive civic practice, rhetoric has played a central role in the Western...

, litotes (icon, us or l)
is a figure of speech

Figures of Speech

Figures of Speech is a hip hop group consisting of MCs Eve and Jyant. They performed at the Good Life Cafe in the early 1990s and were featured on the Project Blowed compilation....

 in which understatement

Understatement

Understatement is a form of speech which contains an expression of less strength than what would be expected. This is not to be confused with euphemism, where a polite phrase is used in place of a harsher or more offensive expression....

 is employed for rhetorical effect when an idea is expressed by a denial of its opposite, principally via double negative

Double negative

A double negative occurs when two forms of negation are used in the same sentence. Multiple negation is the more general term referring to the occurrence of more than one negative in a clause....

s.
For example, rather than saying that something is attractive (or even very attractive), one might merely say it is "not unattractive."

Litotes is a form of understatement

Understatement

Understatement is a form of speech which contains an expression of less strength than what would be expected. This is not to be confused with euphemism, where a polite phrase is used in place of a harsher or more offensive expression....

, always deliberate and with the intention of emphasis

Emphasis

Emphasis or emphatic may refer to:* Emphasis , intentional alteration of the amplitude-vs.-frequency characteristics of the signal to reduce adverse effects of noise...

.