challenge on

challenge someone on something

to dispute someone's statement, remarks, or position. I think Fred is wrong, but I won't challenge him on his estimate.

Name	Pronounced	Usage
Bilyana	-	Bulgarian
Janet	['dʒænit]
Chasity	CHAS-i-tee	English
Hwan	hwahn	Korean
Berthold	BERT-hawlt	German (Archaic)
Enguerrand	-	Medieval French