The term 'real eye-opener' can be summarized by two crossword solutions: TONIC (5 letters) and SHOCKER (7 letters). A TONIC is a medicine or other substance taken to give a feeling of vigor or well-being, while a SHOCKER is something that causes a strong emotional reaction, usually one of surprise or disbelief. Therefore, the term 'real eye-opener' can be interpreted as something that has a powerful effect on someone, either physically or emotionally.