A family of Microsoft word processing software products for creating web, email, and print documents.
This sounds like a typical issue where portions of the document carry a Language attribute for which Mac Word does not have Proofing Tools. It's difficult to be certain without having the document in hand. As Charles indicated this can be due to pasted content copied from other sources, especially web sites.
The dash means that some text has the Do Not Check property applied but other portions do not.
Use Command+A to Select All then go to Tools> Language to select the correct one... Just be sure that those portions aren't intended to carry the attribute they already have. NOTE: Do Not click the Default button, just click OK.
If that doesn't provide the solution please include these factors in your reply:
- Specific Version Number & type of License for the Office software as shown in Word> About Microsoft Word
- Specific Version Number of macOS as indicated in **> About This Mac**
- Clarification of what you mean by dictionary icon
- Screen shots depicting the issue