What term describes the situation when the ordinary meaning of a word is the opposite of the author's intended message?

The term that describes a situation where the ordinary meaning of a word is the opposite of the author's intended message is irony. Irony often involves a contrast between expectations and reality, where a statement or situation has an underlying meaning that is different from (or even the opposite of) what is explicitly stated. In literature and speech, irony can be used to convey a deeper or more complex meaning, often highlighting the discrepancies between appearances and underlying truths.

In contrast, metaphor refers to a figure of speech that implies a comparison between two unlike things without using "like" or "as," whereas allegory involves a narrative in which characters and events symbolize deeper moral or political meanings. Hyperbole employs exaggerated statements that aren’t meant to be taken literally, often for emphasis or effect. Each of these terms serves a unique purpose in writing but does not capture the specific sense of contradiction inherent in irony.