catch somebody on the hop1 → catch somebody by surprise, catch somebody off guard, catch somebody napping/unawares
2 READYto do something when someone is not expecting it and is not ready 使某人措手不及catch somebody on the hop• Many politicians have been caught on the hop by a good interviewer.• Yes, I think I caught her on the hop.• The dramatic fall in share prices caught even the experts on the hop.• They catch you on the hop.• Sorry about the mess but you caught me on the hop like.• You caught us on the hop there, ol' buddy.
→ catch somebody on the hop at hop2(1)