An enemy
Psychological (Freud)
An enemy in a dream often embodies a rejected, repressed part of the self that one fights in another. What we fear or hate in him may mirror the very drives and traits we refuse to grant ourselves.
Oriental reading
By Oriental reading an enemy heralds, depending on the dream's outcome, either an approaching conflict or, if one prevails over him, one's own triumph and the end of a worry. Reconciling with an enemy is widely taken as a sign of peace and relief.
People
Dream interpretation is for self-reflection and entertainment — it is not a medical or psychological diagnosis.