There are a variety of synonyms for the phrase "snapping at" that convey similar meanings. For example, "lashing out" or "flaring up" often implies a sudden and potentially aggressive reaction. "Biting" or "snarling" is usually used when referring to an animal's response, while "sniping" and "criticizing" suggest a more verbal and calculated attack. "Growling" can also be used to imply a low-key and persistent irritation that may eventually escalate into a more aggressive outburst. Regardless of the specific word used, these synonyms all convey the idea of reacting quickly and harshly, often without much forethought or consideration.