Animosity is the emotion of hate.
When love is a duality of love & hate, love is the female (anima) emotion and hate is the male (animus) emotion. I sub-consciously love someone who gives me their female emotional energy and I hate someone who withholds it or steals it from me. Animosity is my male emotional reaction to my lack of female love. When I have female love, I value it and when I need female love, I hate it when it is withheld and I hate whomever withholds it from me. When I am sub-consciously driven by my need for emotional energy, I will default to the anima of my female energy or the animus of my male energy.
Enmity is the hatred of mental will.
My mental will determines my choices in alignment with my beliefs. When my will is denied, I hate whomever is denying or blocking my will. I like people who are like me and have a like-minded will or ego sense of self. I hate people with enmity who oppose the will of my ego, with the will of their ego. Enmity is the effect of opposing polarities of mental energy. The mental energy of my intellectual thinking often contrasts with the thinking of other intellectuals. When I believe the reasoning of others to be false, my truth is in enmity with theirs. Enmity is caused by the opposition of contrasting perspectives, driven by the fears of contradictory belief systems.
By the Law of Attraction, like polarities of thinking are attractive and opposing genders of emotion are attractive. Therefore opposing polarities of negative beliefs & reasoning cause enmity and similar genders of negative emotional feeling cause animosity.
Only the pure love of agape is without the hatred of either enmity or animosity.