There are 19 words that start with 'deep'.
| deep | deeps | deepen | 
| deeper | deeply | deepens | 
| deepest | deepened | deepener | 
| deepness | deepeners | deepening | 
| deepfroze | deepwater | deepfreeze | 
| deepfrozen | deepnesses | deepfreezes | 
| deepfreezing | ||
Note: These 19 words that start with 'deep' are found from the USA & Canada version of the tournament Scrabble word list.