Impugn

The father does not impugn her ability to be a good mother.

A language that can pluralize the word “truth” does not thereby impugn the uniqueness of the concept as a whole; “truths” may just refer to several statements, each of which is true, as in “the fundamental truths of science.”

I wouldn't impugn your integrity simply because we have different value systems.

For quotations using this term, see Citations:impugn.

[The fact] that Americans’ trust in government is at historic lows […] makes it easier for politicians to impugn the system – courts, parties, and institutions.