1. A computer-implemented method comprising: selecting a target word from a set of words from a plurality of documents; determining a first subset of words from the set comprising words that are most correlated with the target word; determining a set of values, wherein each value is associated with a correlation between a first word from the first subset and a second word from the first subset, wherein the first word and the second word co-occur with the target word in a particular document of a plurality of documents; and determining, based on the set of values, at least two clusters of words from the first subset.