Devote oneself to something means to DEDICATE and SPEND time and effort on it. This phrase can be broken down into two crossword solutions: DEDICATE (8 letters) and SPEND (5 letters). DEDICATE is defined as to commit or devote oneself to a particular purpose or cause, while SPEND is defined as to use up (time, money, resources, etc.). Therefore, the phrase 'devote oneself to' means to commit and use up time and resources for a particular purpose or cause.