to reproach: to throw a person's fault, real or alleged, in their face with words that shame them in front of others.
This is the action word of a small family. The nouns name the reproach itself and the disgrace it leaves behind (ὀνειδισμός, ὄνειδος); this verb names the act of one person casting a charge at another. The old Greek picture behind it, already in Homer, is throwing something in someone's teeth.
In the world of the New Testament that was never merely private hurt. A person's honor was their standing in the eyes of the community, so a public insult was a verdict: this person is worth less than you thought. That is why the same verb can cover something as brutal as strangers jeering at a dying man and something as ordinary as a giver making the person who asked feel small.
The range runs across territory that English usually splits between two very different words, "revile" and "rebuke":
- hostile abuse the target has done nothing to deserve, as when the men crucified beside Jesus taunt him;
- the insults believers take on because they belong to Jesus, which both he and Peter call a blessing;
- a charge someone genuinely has coming, as when Jesus reproaches towns that saw his works and did not change;
- a giver grumbling at the person who asked, which James says God never does.
Nothing in the Greek word itself settles whether the charge is fair. That is decided by who is speaking and what is true, which is why English translations move between "insult," "revile," "rebuke," and "find fault" from verse to verse.