The dynamic
Fixed meets fixed across a square, which means two people who each hold a position with real stamina and see no particular reason to move first. Scorpio is water and yin: loyalty, intimacy, emotional truth, with Pluto and traditionally Mars supplying intensity. Aquarius is air and yang: principles, ideas, the wider group, with Uranus pushing toward change and Saturn, its traditional ruler, keeping those principles stubbornly consistent. Each is drawn to the other's refusal to be ordinary.
The friction is about what deserves loyalty. Scorpio is loyal to people and expects undivided attention; Aquarius is loyal to ideals and to a wide circle, and bristles at being possessed. When Scorpio asks a personal question, Aquarius may answer with a theory. When Aquarius spends Saturday at a community meeting, Scorpio may count it as a choice against them. Neither backs down easily because neither sign's modality is built for it, so disagreements can freeze rather than resolve. What breaks the stalemate is usually curiosity: both are investigators, one of motive, one of systems.
In love
The attraction is often intellectual first, then suddenly intense. Scorpio wants to know everything about the partner's inner life; Aquarius wants room to keep part of it unexplained. Jealousy and detachment can feed each other: the more Aquarius steps back, the closer Scorpio watches, and the closer Scorpio watches, the further Aquarius steps back. A Venus sign in a friendlier element for either partner can soften this loop considerably. Couples who last tend to agree on explicit boundaries, which suits both: Scorpio gets certainty, Aquarius gets freedom that has been negotiated rather than taken.
As friends
Both enjoy arguing about the things others avoid: power, taboo, how societies really work. Scorpio brings the psychology, Aquarius the sociology. The friendship stays strong while it has a shared project or cause to orbit. It falters if Aquarius treats Scorpio as one of many friends while Scorpio has quietly ranked Aquarius in the inner circle; that mismatch of expectation, never stated, can harden into distance.
At work
Both are hard to move once a decision is made, which makes them excellent at defending a project and poor at pivoting together. Aquarius proposes the unconventional system; Scorpio stress-tests it for hidden weaknesses and political risks. Meetings can stall into polite deadlock. A neutral third colleague, or a rule that any decision gets revisited after a set date, keeps two fixed signs from turning every disagreement into a siege.