What does ironic actually mean?

Irony in its established senses involves a meaningful gap. Verbal irony says the opposite of what is meant, as in calling a downpour lovely weather. Situational irony describes an outcome contrary to what was intended or expected, particularly when the action produces the opposite of its purpose: a fire station burning down, a safety device causing an injury, a person avoiding a flight from fear of crashing and dying in a car on the way home. Dramatic irony occurs when the audience knows something the characters do not, which drives most tragedy. What distinguishes irony from coincidence is that the gap must be pointed, connected to expectation or intention rather than merely improbable.

The Alanis Morissette objection has become the standard reference. Rain on a wedding day, a traffic jam when you are already late, and a free ride when you have already paid are unfortunate coincidences rather than ironies, since nothing about them reverses an intention or subverts an expectation in the required way. Some critics have noted the layered possibility that a song called Ironic containing no irony is itself ironic, which is the kind of argument the internet was built for.

The descriptivist counterpoint deserves stating because it is legitimate. Dictionaries record that the word has broadened in common use toward meaning coincidental or unexpected, and words do shift, as this one already did from a Greek term for feigned ignorance. Merriam-Webster documents the broader sense while noting it is often criticized. So the honest answer has two layers: in careful writing, reserve irony for the reversal of expectation, because using it loosely costs you precision and readers will notice, and in casual speech the broader use is common enough that correcting people is usually a choice about being right rather than about being understood.