The correct reading is ほんぽう. Both 奔 (ほん) and 放 (ほう) are read with their on'yomi, but 放 becomes ぽう due to rendaku after the 'ん' sound. はんぽう is incorrect as 奔 is not はん. This word describes someone or something completely free and often unconventional in behavior or style, without inhibitions or restraints.

正しい読みはほんぽうです。奔（ほん）と放（ほう）は両方とも音読みですが、「ん」の後の放は連濁で「ぽう」となります。はんぽうは奔の読み間違いです。この言葉は、振る舞いやスタイルが型にはまらず、自由奔放な様子を表します。