GovernmentAttic got a list [PDF] of all the vanity plate ideas the DC Dept. of Motor Vehicles has rejected, as of 2012. Here are some of the funniest:
DEJAVUE (this one presumably rejected by a spelling stickler)
NAKEDROB and NAKDROB (apparently Rob tried this twice)
2. Most Commonly Rejected Words
Of words BuzzFeed searched for, “ass” wins the day, having appeared in 359 rejected plates. Interestingly, “cat” and “dog” tied at 71.
This doesn’t include alternate spellings — BuzzFeed counted 8 variations on BIGPIMPN, 9 variants on DAAAMN with multiple A’s, and 6 versions of GO2HELL, including GO2HILL.
Analyses in other states have found that DMVs may have somewhat arbitrary rules for banning plates — Georgia, for instance, banned G0TBEER but not L0VWINE.