What does: Check new search terms mean?

Under " My Shop " → " Search terms " → " New terms " keywords are listed which are conspicuous due to their high search queries. These are usually very “ broad ” or general keywords. 

Because the automatic inclusion of such general keywords can lead to increased costs, these keywords are included in this list for the time being and are not used for recommendations. 

You can then decide for yourself which of these keywords you actually want to have included in the recommendations. If you would like to accept a keyword, just click on the check mark, if not, then select the "x".