* Formal: Due to unforeseen circumstances, I was tardy for the meeting.
* Informal: I'm always tardy for everything, even if I set five alarms.
* Descriptive: The students who arrived tardy were given a warning.
* Humorous: He was so tardy that he missed the entire movie!
The best way to use "tardy" depends on the context of your sentence and the tone you are trying to convey.