锋芒 has both literal and figurative senses. Literally it is the tip of a blade. Figuratively it refers to someone's sharp talent or aggressive ability. Key idioms:
锋芒毕露 (fēngmáng bì lù) — to show all one's talent, making no effort to conceal it;
锋芒内敛 (fēngmáng nèi liǎn) — to keep one's talent understated.