1: a : having no definite form b : being without definite character or nature c : lacking organization or unity
2 : having no real or apparent crystalline form an amorphous mineral
1: The death cult is rather amorphous in nature, making exposing their members or heirarchy rather difficult.
2: Even when studied the gas seems to be amorphous, unaffected by pressure or temperature.
So you’ve got ghosts, blogs, oozes, haunts, cloud-spells, so many places this word is used descriptively in any rpg. Then there’s all the derivatives in character or organization. An amprphous organization would describe a chaotic neutral cult. Some might be open, some might be hidden, this sect might gather for rituals, that sect might only secretly admit their membership to others of the cult. This group might see their purpose to accelerate an event the cult expects in prophocey. That group may simple provide warning to the populus or even attempt to prevent the same event.