As for the etymology the term enemy is derived from Latin language for 'bad friend' (Latin: inimicus). Enemy is a strong word, and emotions associated with the enemy would include anger, hatred, frustration, envy, jealousy, fear, distrust, and possibly grudging respect . As a political concept, an enemy is likely to be met with hate, violence, battle and war. The opposite of an enemy is a friend or ally.
diffusion. 1. The process of rapid random movement of the particles of a liquid or gas which eventually form a uniform mixture. 2. The mixing of substances due to the motion of their particles.
Diffusion is the tendency of molecules to spread into an available space. Without other outside forces at work, substances will diffuse from a more concentrated environment to a less concentrated environment. Passive transport is the diffusion of substances across a membrane. This is a spontaneous process and cellular energy is not expended. Molecules will move from where the substance is more concentrated to where it is less concentrated.