κατιόωkatióō

to rust over; passive, become rusted over: James 5:3.

Greek (New Testament) · G2728

Same root

κατάkatá · G2596(prepositionally) down (in place or time), in varied relations (according to the case (genitive, dative or accusative) with which it is joined)
ἰόςiós · G2447rust (as if emitted by metals); also venom (as emitted by serpents)

Where it appears

Appears 1 times in the Bible.

James 5:3 Your gold and silver are corroded. The very wealth you were counting on will eat away your flesh like fire. This corroded treasure you have hoarded will testify against you on the day of judgment.

Source: G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), public domain.