The most important significance of the deer appearing in a dream relates to the feminine side both in men and women. Carl Gustave Jung has demonstrated through his anima/animus theory that women have a masculine side and men have a feminine side. Therefore, a dream about a deer will mainly symbolize the person's feminine, delicate, gentle, innocent side, independent of gender.
Mirroring the softer side of our personality, the deer in dreams may be a warning that you should not let yourself completely indulge in a love affair as you could be hurt by the partner. In this way, you may become a love fool who gives everything and is treated with indifference.
If the deer is black, it means that you try to reject your emotions and your gentle, harmless side of personality. Moreover, if you hurt or kill the deer in your dream, it means that you really want to suppress the feminine side and become more aggressive and rough, not to be touched by any 'sweet' feeling.
If a man dreams of a deer, this may also symbolize that he wants to conquer a woman.