There are 9 words that start with 'exting'.
| extinguish | extinguished | 
| extinguisher | extinguishes | 
| extinguishers | extinguishing | 
| extinguishable | extinguishment | 
| extinguishments | |
Note: These 9 words that start with 'exting' are found from the USA & Canada version of the tournament Scrabble word list.