check someone up—
1. (also: give someone a check-up) give smb. a medical examination:
- The doctor checked me up and I was told I was in bad shape.
2. establish the truth about smb.; investigate a person:
- The cop doesn’t even take the trouble to check me up, he knows me damn well.
check up on someone— = check someone 2:
- The police checked up on him, and he had an alibi. Several people testified that they saw him at a bar in Rochester.