General:
* Delete
* Remove
* Obliterate
* Wipe out
* Annihilate
* Destroy
* Efface
* Expunge
* Cancel
* Eliminate
* Rub out
For specific contexts:
* Overwrite (for data)
* Clear (for a screen or display)
* Blank out (for a memory)
* Scrub (for data or records)
* Strike through (for writing)
The best synonym will depend on the specific context in which you are using the word "erase."