There are 14 words that start with 'quac'.
| quack | quacks | quacky | 
| quacked | quackery | quackier | 
| quacking | quackish | quackism | 
| quackiest | quackisms | quackeries | 
| quacksalver | quacksalvers | |
Note: These 14 words that start with 'quac' are found from the USA & Canada version of the tournament Scrabble word list.