The antonyms for the word "more retentive" are forgetful, absent-minded, negligent, careless, inattentive, indifferent, and unmindful. If someone is forgetful, they have a hard time retaining information, which can lead to problems in their personal and professional life. Being absent-minded means that someone is easily distracted and can't focus on important details. Negligence refers to being careless or lacking attention to detail, while being inattentive means not paying attention. Indifference suggests a lack of interest or concern, and being unmindful means not being mindful or aware of important details. In contrast, people who are more retentive are able to remember information and details more easily.