Hedonism was the belief that one should strive for pleasure above all else.
In 2267, Leonard McCoy described the society on Argelius II as completely hedonistic. (TOS: "Wolf in the Fold")
In Data's 2369 ode Ode to Spot, he described Spot's purr,saying it "obviates your basic hedonistic predilection". (TNG: "Schisms")
In 2372, Quark questioned why Bajorans felt the need to have a time of cleansing, as they were not known for being hedonistic in general. (DS9: "Bar Association")