An opposition is just that; when two things are opposite each other. It’s an astrological term for when two planets are opposite each other. This can refer to either when both planets are in transit, or when a transiting planet is making an opposition to one of the planets or points in your natal astrology chart--or even between two natal planets. Oppositions usually indicate that there’s a tug of war going on between the energy of those planets. It’s considered a challenging aspect, but not necessarily a bad one.