Explanation:

- The word "moil" means to work hard, toil, or labor.

- Option 1: Cultivate – This means to prepare and use land for crops or gardening, which is also a form of work.

- Option 2: Grow – This usually refers to increasing in size, number, or importance, often requiring effort or cultivation.

- Option 3: Discourage – This means to prevent or try to prevent something by showing disapproval or creating difficulties, or to make someone less willing to do something (opposite of the motivation to work hard).

- Option 4: Work – This is almost a direct synonym of moil as it also means to labor or put in effort.

The correct answer is Option 3: Discourage.