I read from dirty to disability.

It seems that the phrase "dirty pool" came from billiards.

https://en.wiktionary.org/wiki/dirty_pool

Another name for Dis Pater (Roman God of the Underworld) is Rex Infernus which is objectively much cooler. 

https://en.wikipedia.org/wiki/D%C4%ABs_Pater

The word of the episode is "dirty word".

https://en.wiktionary.org/wiki/Category:English_swear_words

 ...