"Burn the candle ends" means to work late into the night, usually to complete a task or to catch up on unfinished work. There are a variety of synonyms for this phrase, namely "work overtime," "burn the midnight oil," "grind late," "pull an all-nighter," and "stay up late." These phrases all indicate a prolonged period of work, often at the expense of rest and relaxation. While working hard is commendable, it is important to remember that it is equally important to take care of oneself and balance work with rest to maintain overall health and wellbeing.