To do a sterling job is to do an excellent job, and specifically a reliable, solid one. It is a characteristically British compliment, a little hearty in tone, and it turns up in a family of near-identical phrases: sterling work, sterling effort, sterling service. The word being reached for in each case is ‘sterling’ as in sterling silver, that is, silver of guaranteed quality. It has nothing to do with the Scottish town of Stirling, despite the occasional misspelling.
What’s the origin of the phrase ‘sterling job’?
A sterling was originally an English silver penny of the Norman period. The word is on record from the late 11th or early 12th century in the French-style spelling ‘esterlin’, and in the Anglo-Latin form ‘sterlingus’ by 1180. Where it came from is less settled than you might expect for a word so central to English money. The explanation usually preferred is that it derives from Old English ‘steorra’ (star) plus the diminutive suffix ‘-ling’, so ‘little star’, after the small star stamped on some Norman pennies. Even that has its doubters: numismatists point out that starred pennies made up only a small fraction of the coinage, and an alternative derivation from a word meaning ‘strong’ or ‘stout’ has been suggested. One theory that can be set aside is the once-popular idea that sterling is short for ‘Easterling’, a name for merchants and moneyers from the Baltic and north Germany. That story circulated among antiquarians from the 16th century onwards but has long been rejected by etymologists.
A pound sterling was, literally, a pound weight of sterlings, around 240 of the silver pennies. Because the fineness of that silver was fixed by national standard, ‘sterling’ came to stand for guaranteed quality itself. By around 1400 it was in use as an adjective meaning ‘of standard national value’ when applied to money, and it was later applied to silver of the required purity, which is why we still speak of sterling silver.
The figurative leap to people and their efforts came in the 17th century, when ‘sterling’ began to be applied to qualities and principles that were, like a good coin, capable of standing a test. The writer James Howell, in a letter published in 1647, praised judgement that was ‘sound and sterling’. From that sense flow the modern collocations: sterling qualities, sterling character, sterling work. ‘Sterling job’ itself is simply the conversational modern end of this line, a stock piece of British praise for work that, like coin of the realm in mint condition, can be trusted to be exactly what it claims.