练功

练功	liàn gōng	to do tai chi / to practice kung-fu (or other martial art) / to train (for dancing, acrobatics etc)
练	liàn	to practice / to train / to drill / to perfect (one's skill) / exercise / (literary) white silk / to boil and scour raw silk
功	gōng	meritorious deed or service / achievement / result / service / accomplishment / work (physics)