“Unequal weights”
Unequal weights are detestable to the LORD, and dishonest scales are no good. (Proverbs 20:23 BSB)
What it sounds like today
A vague condemnation of unfairness in the abstract.
The cultural key
Before standardized coins and scales, goods were weighed on a balance against stone weights carried in a pouch, and 'unequal weights' names a specific, common fraud. A crooked merchant kept two sets of stones marked the same: a heavier one to weigh out what customers were buying (so they got less than they paid for) and a lighter one to weigh what he was buying from them (so he paid for less than he received). The Hebrew is literally 'a stone and a stone', two different stones for the same nominal weight. The Law explicitly forbade carrying 'two kinds of weights, a heavy and a light,' in your bag (Deuteronomy 25:13-16). So this is not a general sigh about unfairness but a pointed strike at a precise, everyday swindle that God 'detests.'
Recovered meaning
'Unequal weights' names a specific scam: the merchant's two sets of balance-stones, heavy to sell by and light to buy by, rigged to cheat at both ends. God detests the rigged scale, not unfairness in the abstract.