σήπω

From the study of James 5:2

Range of meaning

To make rotten. In the intransitive perfect used here, 'to be rotten, to have decayed'. It is used for organic matter going bad: spoiled food, rotting wood, decomposing flesh and festering wounds. The related noun sēpsis means 'putrefaction'.

Against the English

BSB, ESV, NASB and YLT give 'have rotted', which is exact. KJV and WEB give 'are corrupted', which in 1611 meant physically decayed (compare Matt 6:19 KJV, 'moth and rust doth corrupt'). Today 'corrupted' mostly suggests moral corruption or damaged computer data. NLT's 'is rotting away' turns the completed state into a process still going on.

How it drifted

The English word 'corrupt' moved from mostly physical decay toward moral and institutional dishonesty. As a result, the KJV/WEB 'riches are corrupted' can sound like 'ill-gotten' or 'dishonest' wealth. That idea does come up in verse 4, but it is not what this verb says.

Used elsewhere in the period

It occurs only here in the New Testament. In the Greek Old Testament (LXX), Job 19:20 says 'my flesh has rotted' and Job 40:12 uses the verb of the wicked rotting. Sirach 14:19 says 'every work that rots (sēpomenon) will fail', which is close to James's idea that perishable things come to nothing. Classical writers use it for food and flesh going bad (LSJ).