The Term Mapper will map back up to terms in the specified GO Subset (GO Slim). These predetermined bins can be customised by using your own Subset, or for most organisms the Generic GO Subsets will suffice. You might explore the other subsets and use the SGD Subset if you have an organism more closely related to Saccharomyces cerevisiae, for example. This tool is probably what you are looking for to get a summary of GO terms.
The Term Finder is not limited to predetermined bins but will just show significant shared GO terms. This tool might be helpful if you find the bins in Term Mapper are too general to be informative.