The simplest I've been able to use in a real game was:

Law: Stability
Chaos: Change

Then what would Neutrality represent? In this game, it was Cycles, which are both stable (in that they repeat) and also changing (in that each stage of the cycle ends and progresses into the next).

So, for example, the cycle of the natural year would be in the domain of Neutrality, but spring and autumn were Chaotic (because daylight hours, temperature, and weather were in flux), while winter and summer were more stable, and thus Lawful.

Tides were Neutral; storms were Chaotic.

Institutions would usually begin as Chaotic, and then over time slowly become Neutral (if they were cyclic) or Lawful (if they were more static).