Old words for apathy

I finally found a good example of Google's Ngram viewer for the prevalence of words over time. The Victorian words torpor and languor have been supplanted by apathy and lethargy, all with very similar meaning. I find it humorous that "apathy" was particularly prevalent in the 1960's.

torpor - inactivity resulting from lethargy and lack of vigor or energy
languor - showing an unusual lack of energy
lethargy - showing an unusual lack of energy
lassitude - weakness characterized by a lack of vitality or energy
listlessness - inactivity resulting from lethargy and lack of vigor or energy
inanition - exhaustion resulting from lack of food