For the sake of a beautiful word he will have mercy neither for his mother nor father

[GeneD]

There is the Russian expression "Ради красного словца не пожалеет ни мать, ни отца". I've got curious whether there is something similar in English. The expression could be roughly translated as "For the sake of a beautiful word he will have mercy neither for his mother nor father". It means that a person showing off with his "knowledge" or fancy vocabulary is ready to say bad things about his close friends, relatives and the like. What expressions would you use to describe such behaviour?

 

[GeneD]

Or maybe it should be...
For the sake of a beautiful word he will spare neither his mother nor father.

Would you understand the expression if you saw it phrased this way? I guess there are no English counterparts for it...

 

[jutfrank]

I'd say that's better with spare, yes.

I think I would get at least a vague understanding of what is meant.

 

[abaka]

In pre-Regency style, I'd offer

He would sacrifice his parents both, to be thought a wit.

I can't think of any equivalent proverb in English, but, as Darcy says in Pride and Prejudice, "I should as soon call her mother a wit".