Your idea isn't something that Word supports. You might be able to code it in VBA, but it'd be a load on your system.
As a workaround, you can create a character format that can apply bold and a color.
Word support Paragraph, Character, and Linked Paragraph/Character formats, denoted by the Paragraph Mark, lower case a, and both, respectively:
In the above, Strong is a Character style and List Paragraph is a Paragraph style. Quote and Intense Quote a Linked styles, meaning you can apply either of them as a Character style when you use them on selected text. Word applies it as a Paragraph format when you don't have any selected text, so wherever the text cursor resides is the paragraph where Word applied that format.
To make a Character style:
For example, enter a word that you want bold and blue and apply that formatting:
Next, click the Create New Style Button on the Styles dialog:
On the Create New Styles from Formatting dialog, give your new style a name, select Character as the Style Type, and if you wish, select "New documents based on this template" if you will need this in your document template (probably normal.dotm):
Now your character style will appear on the Styles dialog and you can apply it to any selected text.