Soylo is a derogatory name given to the movie "Solo: a star wars story". The word comes from a combination of "soy" and "Solo". Soy is a reference to Soyboys, effeminate and weak males with low testosterone who consume soy products (which is rumoured to cause low testosterone levels).

This movies has gained this name due to character "Solo" in "solo: a star wars story" being effeminate, submissive, and not at all like "Solo" from the original star wars series. The movie is also part of Disney's star wars serious, which has noticeable female supremacist overtones. In general, soyboys are the only group of males that will actively submit to the demands of female supremacists, and therefore they are the only males that would be involved with star wars willingly.

Soylo is a derogatory term for the Movie "Solo a StarWars Story" used mostly by insecure men who feel threatened by the idea of women being presented in leading roles next to leading males.

The term was coined by a Alt-right comic book artists belief that consumption of Soy reduces masculinity (Compensating insults for ones lack of masculinity)

The term is also thrown at StarWars Fans as "Soyboy" as they believe that those who enjoy StarWars are submissive to women. Ignoring the fact that canon shows high level of reverence to legacy characters and features more males in important roles than females to this day.

Some of this stems from the idea that Han Solo in the movie is submissive compared to how we find him in A new Hope.
However in truth outside of age and experience he is the same character and is how he became the man we meet in ANH.