Risk is the possibility of loss by unforseen happenings. it may be categorised as monetary and non- monetary. in financial parlance risk is the possiblity of loss in your investments made (either the capital u had invested, returns or both).
return is the expected value from an investment which has a risk associated with it. for ex: investing in stock market has a equity risk involved with it. generally returns are based on risk levels.
higher the risk higher the return and the vice versa