From Longman Dictionary of Contemporary Englishbe working overtimebe working overtimeinformalDO something/TAKE ACTION to be very active As she put down the phone, her brain was working overtime. His senses were working overtime. → overtime
Examples from the Corpus
be working overtime• His brain was working overtime and he just stood there goggling.• His brain was working overtime now.• He said engineers are working overtime to fix the problems.• Then he announced gleefully that light bulb orders had jumped, suggesting that factories were working overtime.• It looked as if his karma was working overtime.• Meanwhile, aluminum manufacturers were working overtime to supply the armament industry.• Price's wit and sarcasm are working overtime in this production.• Soon after I left them, they were working overtime to fulfil a big order, when there was a breakdown.• Their local maternity unit was working overtime. 