General Antonyms:
* Late: This is the most direct opposite of punctual.
* Tardy: Similar to late, but often implies a less serious degree of unpunctuality.
* Unpunctual: A more formal way of saying late.
* Untimely: This implies being out of time or inappropriate for the situation.
* Belated: Meaning arriving or happening late, often after the expected or desired time.
Other Possibilities:
* Procrastinating: This implies delaying or putting off something until the last minute, leading to unpunctuality.
* Irresponsible: This implies a general lack of regard for time and deadlines, which can lead to unpunctuality.
* Disorganized: This implies a lack of planning and structure, which can contribute to being late.
The best opposite for "punctual" will depend on the specific situation and the intended meaning.