The significantTerms UDF allows the user to query data for significant terms within the results. This identifies terms that appear an unusaully frequently in a specific result set relative to the index. It can be used to identify anomalies in data. This UDF can be used on tokenized text and multi-value and single-value string fields. Example: 
select significantTerms(fieldX), score from collectionName where fieldy = 'my-query' limit 10