Ironic
Etymology
From Greek "eironeia" (dissimulation, feigned ignorance), from "eiron" (one who dissembles) — the stock character who wins by pretending to know less than he does. Socratic irony is the ancestor: feigned ignorance that exposes another’s.
adjective · /eye-RON-ik/
Marked by a pointed gap between what is said or expected and what is actually meant or happens.
What it names
Reach for it when an outcome mockingly reverses its own intent, or words say the opposite of what they mean — not merely when something is odd.
Example
It was genuinely ironic that the fire station burned down — the one building meant to be safe from fire.
Related idea
The word people reach for by mistake is coincidental: a coincidence is two things merely co-occurring, while irony needs a meaningful reversal of expectation. Rain on your wedding day is unlucky, not ironic; a lifeguard drowning is.