If you do, get, or give something in lieu, you do, get, or give it instead of something else, because the two things are considered to have the same value or importance.
[mainly British, formal]
...an increased salary or time off in lieu.
See full dictionary entry for lieu
Examples of 'in lieu' in a sentence
in lieu
Those who do the weekend festival stint get time off in lieu.
Times, Sunday Times (2007)
Can we make it compulsory for them to come in and do we have to pay them extra or can we give a day in lieu?