The antonym for "un-forgetful" is forgetful, which means being prone to forgetting things. Forgetful people may forget names, appointments, or important details. They may have trouble remembering passwords, where they put their keys, or whether they turned off the stove. Other antonyms include oblivious, neglectful, and absent-minded, all of which describe someone who is not able to remember things easily. Forgetfulness can be caused by stress, lack of sleep, depression, or as a side effect of medication. Developing good memory strategies and techniques like creating memory associations, and being more mindful and present can help reduce forgetfulness.