Right off bat is a common phrase used to indicate an immediate or initial action or response. However, there are several synonyms that can be used in place of this phrase to convey the same meaning. Some alternatives include "right away," "immediately," "from the get-go," "right out of the gate," or simply "at the outset." These terms all imply a sense of urgency or expedience, making them suitable replacements for "right off bat." Whether you're writing in a professional context or speaking casually, using one of these synonyms can help to diversify your vocabulary and add variety to your language.