Here's a breakdown:
* Pleonasm: The use of more words than necessary to express an idea. This often involves using two words that mean essentially the same thing, creating redundancy.
While "great big" is a classic example, other common pleonasms include:
* Free gift (gifts are inherently free)
* ATM machine (ATM stands for Automated Teller Machine)
* PIN number (PIN already means Personal Identification Number)
Note: While pleonasms are often considered grammatically incorrect, they can sometimes be used for emphasis or stylistic effect. However, in formal writing, it's generally best to avoid them.