keep someone on the hop
keep (one) on the hop
1. To keep one in a state of unpreparedness or uncertainty. The rapid advances in technology have kept cyber-security officials on the hop in recent years.
2. To keep one very busy or in a hectic or chaotic state. The boss has kept us on the hop so that we get these projects done before the break. Having six kids definitely keeps you on the hop, but I wouldn't have it any other way.
keep someone on the hopBRITISH
If you keep someone on the hop, you cause them problems by doing things they do not expect. Better policing is keeping the drug traffickers on the hop. Compare with catch someone on the hop.