This plugin can add rel=”noindex,nofollow” to archive, tag, and category links. You can configure exactly which links are given which attributes. For instance, you could add rel=”noindex,nofollow” to all of your tag links, rel=”noindex” to all of your archive links, and nothing to your category links.

Noindex/Nofollow links

This plugin can add rel="noindex,nofollow" to archive, tag, and category links. You can configure exactly which links are given which attrib …

amodoke

This plugin lets you Noindex Nofollow All Posts in a category. 
Simply go to Posts > Categories, and click on any category’s EDIT link. 
There you can just “tick” the relevant option you need. 
The plugin will then add a “noindex” or/and “nofollow” line in all posts in that category.
A few notes about the sections above:
<ul>
<li>DigitalChef.in – Madhu Ramrakhyani</li>
<li>This plugin lets you Noindex Nofollow All Posts in a category.</li>
<li>“3.0” is the lowest version that the plugin will work on</li>
<li>“4.7” is the highest version that you’ve successfully used to test the plugin. Note that it might work on 
higher versions… this is just the highest one you’ve verified.</li>
</ul>

NoIndex NoFollow  All Posts

This plugin lets you Noindex Nofollow All Posts in a category.

Noindex/Nofollow links vs NoIndex NoFollow All Posts