There are 15 words that start with 'foul'.
| foul | fouls | fouled | 
| fouler | foully | foulard | 
| foulest | fouling | foulards | 
| foulings | foulness | foulbrood | 
| foulbroods | foulnesses | foulmouthed | 
Note: These 15 words that start with 'foul' are found from the USA & Canada version of the tournament Scrabble word list.