锻炼

锻炼	duàn liàn	to toughen / to temper / to engage in physical exercise / to work out / (fig.) to develop one's skills / to train oneself
锻	duàn	to forge / to discipline / wrought
炼	liàn	to refine; to smelt / to heat or forge (in fire)
炼	liàn	to refine; to temper (variant of 炼) / to polish (wording)