There are 17 words that start with 'postf'.
| postfix | postface | postfire |
| postform | postfaces | postfault |
| postfixal | postfixed | postfixes |
| postforms | postfixing | postflight |
| postformed | postfreeze | postforming |
| postfeminist | postfracture | |
Note: These 17 words that start with 'postf' are found from the USA & Canada version of the tournament Scrabble word list.