KEEP SB ON THEIR TOES


Meaning of KEEP SB ON THEIR TOES in English

to make sure that sb is ready to deal with anything that might happen by doing things that they are not expecting :

Surprise visits help to keep the staff on their toes.

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.