Did you know you can look up words in a dictionary without ever leaving your Word document? Right-click the word in question, go to Look Up and select the dictionary option.
What about the built-in thesaurus? I use that one all the time. Just right-click the word you want to find an alternative for and select Synonyms. (Shift + F7 is the keyboard shortcuts)
And if you still can’t find what you need you can also search the web without ever leaving your document. Right-click what you want to search for, go to Look Up and select the Bing option. Your search results will be displayed in the Research box to the right of your screen.
If you prefer, you can even switch this to use Google or other search sites instead of Bing.