Although this sounds like a nasty medical complaint, it is in fact a barrier to a good writing style.
A pleonasm occurs when unnecessary or redundant words are used. They simply add bulk to a sentence without adding any extra content. Below are some examples of sentences containing a pleonasm. The redundant words have been highlighted. Omitting these words simply makes the sentences more concise.
Jill saw the building burning down with her own eyes. (She must have seen it with her own eyes.)
The vote was completely and totally unanimous. (A unanimous vote cannot be anything but complete and total.)
She herself had written her autobiography of her own life in just two weeks. (She must have written her autobiography, by definition. The biography must have been of her life.)
Tim and his friends decided to co-operate together on their project. (Co-operating involves working together, by definition).
It was his usual, habitual custom to have a bacon sandwich for breakfast. (A custom is always usual and habitual.)
There are lists of common pleonasms on line. One such list can be found at
While reading such lists is quite entertaining, it is impossible to remember all the different traps you could fall into. As with many aspects of good style, there is no substitute for rigorous proof reading.
Test your ability to spot pleonasms with this exercise.