Dirty words 'litter' his vocabulary. [=his vocabulary includes many dirty words; he says a lot of dirty words]
('chiefly US') a 'litter box' = ('Brit') a 'litter tray' [=a container holding litter for a cat]
Of all the cars on the market, this one is clearly 'the pick of the litter'. [=the best one]
(..) And I have kept my word. Once the queen mother's trial is concluded, Brother Loras is free to leave. And where is the queen mother? Her litter never left the Red Keep. It appears the queen mother doesn't wish to attend her own trial. Go to the Red Keep and show her the way. Get the others. (..)2016 TvShow: Game of Thrones Title: The Winds of Winter Season: 6 Episode 10