I see wavy red or green underlines in a document

Cause: Word uses a red underline to indicate a spelling error.

Solution: Correct the spelling error.
Solution: Have Word ignore the word or add it to the spelling dictionary.
Solution: Turn off automatic checking of spelling.

Cause: Word uses a green underline to indicate a grammar error.

Solution: Correct the grammar error.
Solution: Have Word ignore the grammar error.
Solution: Turn off automatic grammar checking.