Pioneer/ˌpaɪəˈnɪr/ Definition 1 of 3Pro Tip 1/3First Achiever Refers to someone who accomplishes something no one else has before. Marie Curie was a pioneer in the field of radioactivity. Pro Tip 2/3Historical Impact Often used when someone's actions have made a significant impact on history. The Wright brothers are revered as pioneers of aviation. Pro Tip 3/3Positive Connotation Implies admiration and positive judgment towards the person's actions. She is widely recognized as a pioneer for women's rights.