George Carlin said he was sick and tired of how misused "ironic" was getting in the world. The true definition is "when something happens in the exact opposite of what you expect."
I remember him saying this once in one of his books.
If a diabetic is hit by a truck, it's a normal death.
If a diabetic is hit by a sugar truck, it's an odd and tragic death.
If a diabetic is hit by an insulin truck, it's a coincidental and oddly poetic death.
But if a diabetic is on his way to get some insulin and he gets hit by an insulin truck, then that's ironic.
It was also a background plot device in Teaching Mrs. Tingle.