闯 is a compound ideograph written with the character 马 "Horse" inside the radical 门, "Gate, Door". The character 闯 visualizes a horse charging through a set of gates similar to how soldiers in ancient China would charge the gates of an enemy stronghold on horseback.
闯 means to rush, charge, dash, or to break through. It is combined with other characters to form words such as: 闯荡 (chuǎng dàng), "well-traveled, adventurous"; 闯祸 (chuǎng huò), "to get into trouble"; and 闯入 (chuǎng rù) "intrude".