The phrase "was up" is a slang greeting used to inquire about someone's well-being or to initiate a casual conversation. Some synonyms for "was up" include "hello," "what's happening," "howdy," "hey," "hi," "holla," and "yo." These phrases are common colloquial expressions used in informal settings to greet friends or acquaintances and start a conversation. Depending on the tone and context, other synonyms for "was up" could be "how's it going," "what's new," or "what's good." Using synonyms for "was up" can add variety to one's social interaction and help them connect with others more easily.