"In line" is a phrase that means waiting in a queue or following a specific order or direction. There are several synonyms for this phrase, including "in queue," "waiting in a line," "conforming," "following," "obeying," "complying," and "in alignment." Other synonyms that could be used include "standing in line," "queueing," "lining up," and "in sequence." These synonyms can be used in various contexts, such as waiting in line at a restaurant, following a set of instructions, or conforming to social norms. Using different synonyms for "in line" can help to add variety and interest to your writing and speech.