In the Spelling & Grammar Preferences. Go to Word> Preferences & clear the
checks for 'Check spelling as you type' & 'Check grammar as you type'.
Just for future reference you might try having a go at any program's Help
before taking the time to search elsewhere for info about its features & how
to use them. Granted, Office 2008 Help in general is significantly less than
it should be, but this particular topic is fully covered:
Turn off automatic spelling checking
HTH |:>)
Bob Jones
[MVP] Office:Mac