The phrase "burn daylight" is an idiom that means to waste time or to do something unproductive. There are several synonyms for this phrase, all of which convey the same idea. One such synonym is "waste time," which is self-explanatory in meaning. Another synonym is "fritter away," which suggests a careless or thoughtless use of time. "Idle away" is another common synonym, implying a kind of laziness or lack of motivation. "Kill time" is another phrase that can be used interchangeably with "burn daylight." Ultimately, all of these synonyms convey the same meaning, that of wasting time that could be better spent on more productive pursuits.