There are 13 words that start with 'opin'.
| opine | oping |
| opined | opines |
| opining | opinion |
| opinions | opinioned |
| opinionated | opinionative |
| opinionatedly | opinionatively |
| opinionatedness | |
Note: These 13 words that start with 'opin' are found from the USA & Canada version of the tournament Scrabble word list.