Something which is mediocre is not great. If you describe something as being mediocre it means it is of average or medium quality, not outstanding or notable in any way.

1. I didn't really enjoy the movie. I was expecting it to be good but it was only mediocre at best.
2. The food in that restaurant was pretty mediocre. I wouldn't go again.

1. Our latest marketing campaign only produced mediocre results. We will need to try something different next time.
2. The negotiations resulted in a mediocre outcome for us. We got the deal over the line but not all our terms were met. 
3. Janice is the best asset that the company has. Everyone else is mediocre in comparison.