@seventy one and @WFred:
This issue was never present until I purchased a new iMac with OS X Mavericks. I was on a 2007 (purchased in 2008) iMac previously running the latest OS X Mountain Lion--without any such issue.
I'm not having this issue anywhere except for MS Word, and now too with Excel--so it seems the MS Office (I'm running MS Office 2011 for Mac) is the only culprit.
Seems I do not have this issue with any of my other apps: Adobe Creative Suite 5 (InDesign, Photoshop, Illustrator, Dreamweaver, etc.). I also just experimented with Pages which does not have this issue either. My browser text does not have issues either (Safari and/or Firefox).
So it's only with MS Office apps it seems.