废寝忘食，汉语成语，字面意思是顾不能睡觉，忘记了吃饭。形容很勤奋专心。可以翻译为（be so absorbed and occupied as to）forget all about eating and sleeping或skip ones meals and sleep。
例句：
废寝忘食地工作
Devote oneself heart and soul to ones work
有时她甚至废寝忘食，一直工作到深夜。
Sometimes she even forgets to eat and rest and works1 until late night.