There are 17 words that start with 'lack'.
| lack | lacks | 
| lacked | lacker | 
| lackey | lackers | 
| lackeys | lacking | 
| lackaday | lackered | 
| lackeyed | lackering | 
| lackeying | lackluster | 
| lacklusters | lackadaisical | 
| lackadaisically | |
Note: These 17 words that start with 'lack' are found from the USA & Canada version of the tournament Scrabble word list.