There are 11 words that start with 'opposi'.
| opposing | opposite | 
| opposites | oppositely | 
| opposition | oppositions | 
| oppositeness | oppositional | 
| oppositionist | oppositenesses | 
| oppositionists | |
Note: These 11 words that start with 'opposi' are found from the USA & Canada version of the tournament Scrabble word list.