To detract from (something); to disparage, belittle.
To remove a part, to detract from (a quality of excellence, authority etc.).
To act in a manner below oneself; to debase oneself.
To take away (something from something else) in a way which leaves it lessened.
To untruthfully speak of another in a belittling, deprecative, slighting manner, either in person or in absentia.
To speak nonsense or to lie.