"Order back" can have a few different meanings, depending on the context. Sometimes it refers to a situation where you need to return something that you previously ordered, or to cancel an order that hasn't yet been fulfilled. Other times it's used to describe the act of enforcing a previous directive or command that had been given. Synonyms for "order back" in these cases could include words like "retrieve," "recall," "rescind," "repeal," "countermand," or "annul." Another meaning of "order back" is to request someone to return to a certain location, in which case synonyms might include "summon," "recall," "call in," or "bring back".