Understatement

[Sarah]

The act of understating, or the condition of being understated;that which is understated; a statement below the truth.

[Sarah]

to state to weakly, or without emphasis

[Sarah]

1. expressing with restraint or lack of emphasis, usually used for an [ironic' or [rhetorical] effect.

2.basically a figure of speech that writers use to subtly make a situation less important or serious than it really is.

[Becky]

a statement that describes something in a way that makes it seem less important, serious, bad, etc. than it really is, or the act of making such statements:

[Agnes]

The presentation of something as being smaller, worse, or less important than it actually is.