There are 15 11-letter words that start with 'ef'.
| effacements | effectively | effectivity |
| effectually | effectuated | effectuates |
| effeminates | effervesced | effervesces |
| efficacious | efficiently | effloresced |
| effloresces | effortfully | effulgences |
Note: These 15 11-letter words that start with 'ef' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with eff, eft, efs.
3-letter words start with 'ef' (3)