The Greek adjective anaítios (G338) means "not guilty," "without cause," or "innocent of a charge." It appears twice in the New Testament: in Matthew 12:5 (priests who work on the Sabbath are "innocent/guiltless") and Matthew 12:7 ("you would not have condemned the innocent").
It combines the negative an- with aitia (cause, charge, blame), meaning "without cause for accusation."
Jesus' double use of anaítios in Matthew 12 is a masterstroke of legal and theological argument. He first demonstrates from the Law itself that priests performing Sabbath duties are innocent (Matthew 12:5), then applies a greater-than-temple principle: if temple service justifies apparent Sabbath violation, how much more does serving the Lord of the Sabbath himself?
The second use is a devastating rebuke: the Pharisees had condemned "the innocent" (Matthew 12:7). They were so focused on Sabbath rules that they had condemned the very One who gave the Sabbath. The anaítios — the truly innocent One — stood before them, and they brought charges against Him. This irony reaches its climax at the cross, where the only truly innocent man bore the guilt of all.