There are 10 words that start with 'vain'.
| vain | vainer | 
| vainly | vainest | 
| vainness | vainglory | 
| vainnesses | vainglories | 
| vainglorious | vaingloriously | 
Note: These 10 words that start with 'vain' are found from the USA & Canada version of the tournament Scrabble word list.