What is another word for working fingers to bone?
Pronunciation: [wˈɜːkɪŋ fˈɪŋɡəz tə bˈə͡ʊn] (IPA) 
There are several other phrases that can be used as synonyms for "working fingers to bone". One possible alternative is "slaving away", which implies hard and unrelenting work. Another alternative is "burning the midnight oil", which suggests working late into the night and sacrificing sleep. "Sweating bullets" is another phrase that is used to describe working hard under pressure or stress. "Putting in long hours" is also a possible synonym that suggests working for an extended period of time. Finally, "knocking oneself out" is a phrase that can be used to describe working extremely hard or exerting oneself to the fullest.
