blocking taxonomy terms from being indexed

Have you noticed through your Google account that there are items being indexed that shouldn't have been?   One for me was taxonomy terms.  Not important to be followed.

1. Being indexed on my sitemap (do I just erase those entries on the XML file?)
2. Being crawled (I am guessing this is with a robots.txt file though I have never created one before)
3. Being viewed (stumbled upon) -> if this even possible to block?

Resolve these quickly by simply adding disallow in robots.txt file.

Disallow: /taxonomy/

And add no follow no index on taxonomy pages using the Metatags module (/admin/config/search/metatag)

<meta name="robots" content="noindex, nofollow" />

Clear your cache, rebuild your sitemap and cross check that they are gone.