There are 14 words that start with 'effi'.
| effigy | efficacy |
| effigial | effigies |
| efficient | efficacies |
| efficacity | efficiency |
| efficacious | efficiently |
| efficacities | efficiencies |
| efficaciously | efficaciousness |
Note: These 14 words that start with 'effi' are found from the USA & Canada version of the tournament Scrabble word list.