When you set something loose, it means that you've released it from being restrained, freed it from confinement, or detached it from a fixed position. One synonym for set loose could be "liberate," which means to free from oppression or confinement. Another similar term is "unleash," which is to release or let go of something that was previously held back. "Unmoored" is another metaphorical synonym, which refers to being free from attachment or restraint. You may also use "let loose" or "untether," which describe the act of releasing something from a fixed position or constraint. These synonyms for set loose can be useful to express the act of freeing things from restrictions.