5. The related word presentation device according to claim 4 , wherein the first related word selecting unit is configured to preferentially select a word having a greatest degree of relevance with the search word obtained by the obtaining unit as the first related word from the association dictionary for the attribute obtained by the obtaining unit.
12. The related word presentation device according to claim 5 , wherein the first related word selecting unit is configured to further select a word having a greater degree of relevance with another search word as a third related word from the association dictionary for the attribute of the other search word in the case where the other search word and the attribute of the other search word have been obtained in a predetermined period prior to the obtainment of the search word by the obtaining unit, and the presentation unit further presents the third related word obtained by the first related word selecting unit.