There are 13 words that start with 'illusi'.
| illusion | illusive | 
| illusions | illusional | 
| illusively | illusionary | 
| illusionism | illusionist | 
| illusionisms | illusionists | 
| illusiveness | illusionistic | 
| illusivenesses | |
Note: These 13 words that start with 'illusi' are found from the USA & Canada version of the tournament Scrabble word list.