WordValeburn the midnight oil
to work late into the night
In more detail
(idiom) to work very hard, especially late into the night or for a long time on something difficult
Examples
- She's been burning the midnight oil to finish her thesis before the deadline.
How to use burn the midnight oil
This idiom describes intense, sustained effort often involving late-night work, typically on something demanding or urgent. It carries a sense of dedication or desperation, and can imply either admirable commitment or unsustainable overwork. The phrase is more common in written English and somewhat formal contexts, and slightly more frequent in British English.
Common phrases
- burn the midnight oil to meet a deadline
- burning the midnight oil on a project
- have to burn the midnight oil
- burning the midnight oil before an exam
- been burning the midnight oil
Synonyms
work late into the night · burn oneself out · toil hard · slave away · work one's fingers to the bone
A common mistake
Learners sometimes use this to mean simply 'working at night' without the connotation of hard effort or difficulty; the idiom implies not just timing but intensity and struggle.
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