By default, Word automatically checks your document for spelling and grammar errors, so you may not even need to run a separate spelling and grammar check. These errors are indicated by coloured wavy lines.

A contextual spelling error occurs when the wrong word is used but the word is spelled correctly. For example, if you write Deer Mr. Theodore at the beginning of a letter, deer is a contextual spelling error because dear should have been used. Deer is spelled correctly, but it is used incorrectly in this letter.