Blameless, faultless, as in Jean's conduct at school is beyond reproach. The phrase employs the verb to reproach in the sense of "censure or rebuke," a usage dating from the early 1500s.

What is being beyond reproach?

: not calling for any criticism His actions were above/beyond reproach.

What does it mean without reproach?

vb tr. 1 to impute blame to (a person) for an action or fault; rebuke. 2 Archaic to bring disgrace or shame upon. n.