A semi-square happens when two astral items have an angle of 45° using an orb of 1° or 2°.
Semi-squares suggest a refusal of integration or unity. The astral items involved in this aspect are like magnets repelling each other when they get too close.
The energy is similar to a refusal to connect or to come to a conclusion. It can be a refusal to go with the flow. It may lead to eternal procrastination and can irritate others.
Semi-squares are neutralized by conjunctions or perseverance. They aggravate quincunx and opposition energies but facilitate the liberation of squares and sesquiquadrate energies. They get trines energy into motion, like light through a prism creates a rainbow.
Related aspects: square, sesquisquare, t-square and grand cross
Other minor and rare aspects: grand trine, quincunx & inconjunct, quintile & biquintile, semi-sextile and yod