honor (someone's) check
To give one money in exchange for a check from someone; to cash a check from someone. The bank said they couldn't honor your check because you didn't have enough funds in your account.
honor someone's check
to accept someone's personal check in payment of an obligation. The clerk at the store wouldn't honor my check. I had to pay cash. The bank didn't honor your check when I tried to deposit it. Please give me cash.