15. A computer program product for generating a synonym list from a natural language query, the computer program product comprising a non-transitory computer usable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method comprising: preparing a first feature vector from a natural language query and preparing a second feature vector from a result of the natural language query; determining, using a processor, whether a combination of a first feature from the first feature vector and a second feature from the second feature vector is included as a synonym pair in the existing thesaurus; and generating the synonym list by adding the combination to the synonym list when the determination is positive.
20. The computer program product according to claim 15 , wherein the synonym list is for a specific purpose.