We found 3 dictionaries that define the word be on the case:

General (2 matching dictionaries)

1. be on the case: Cambridge Advanced Learner's Dictionary
2. be on the case: Longman Dictionary of Contemporary English

Miscellaneous (1 matching dictionary)

3. be on the case: Idioms

▸ Words similar to be on the case ▸ Usage examples for be on the case ▸ Idioms related to be on the case ▸ Wikipedia articles (New!) ▸ Words that often appear near be on the case ▸ Rhymes of be on the case ▸ Invented words related to be on the case