Here are some possibilities:
* Understatement: This is a common rhetorical device where a statement is intentionally made weaker than it could be to emphasize the truth of the matter. For example, "It's a bit chilly outside" could be an understatement if it's actually freezing.
* Litotes: This is a specific type of understatement that uses double negatives to emphasize a point. For example, "It's not bad" implies something is actually quite good.
* Irony: This refers to a statement that conveys a meaning opposite to its literal meaning. Often used for humorous or satirical purposes, it can also be used to express a strong opinion indirectly.
* Euphemism: This is the substitution of a mild or indirect expression for one considered harsh or blunt. It's often used to soften the impact of a potentially negative statement.
It's important to note that these are just some possibilities, and the specific term used will depend on the specific context and the intention of the speaker.