Intent/Attitude, Attention, Relaxation, Pressure, Leverage, Direction
Everything I can think of that is important is in fighting is encompassed in these words...maybe for any skill. The most important underlying thing that makes you good is your intent/attitude/state of mind. If you have that, you can learn the others. The most important word for the nitty gritty of what the study of martial arts entails is leverage. I may change my mind later though.