The word "shacked" has a few synonyms that can be used depending on the context of the sentence. Some common synonyms for "shacked" include housed, lodged, accommodated, harbored, and domiciled. For example, instead of saying "he shacked up with his girlfriend," you could say "he lodged with his girlfriend" or "he housed himself with his girlfriend." Similarly, instead of saying "the criminals shacked up in the abandoned building," you could say "the criminals harbored themselves in the abandoned building" or "the criminals domiciled themselves in the abandoned building." These synonyms can help to add variety to your writing and make it more interesting to read.