Surnames are a fairly recent invention. In most European countries they became common as populations grew and people found they needed a way to distinguish William the blacksmith from William the yeoman when telling a story about one of the their neighbors, or the taxman wanted to make sure both John the baker and John who lived on the hill got dinged for his fair share.
Most European surnames come from one of a few sources. They were patronymics, based on a father or mother’s name (Will’s son became Wilson), place names (Jenny Lake), nicknames or characteristics (Richard Little), and, of course, occupations.
Some of those occupational names are obvious even today.
Jonny Lee Miller may not know anything about grinding grain, but he probably had an ancestor back in the day who ran a mill of some sort. And someone in Carrie Fisher’s past most likely knew his away around a net or a boat.
Some don’t jump out at you until you stop to think about it. Did Donald Trump’s predecessors play a mean hand of bridge, or was there was a herald or trumpeter back in the day? (Think option 2.) Others require a little history. For example, about a century ago, coopers made barrels and casks. Nowadays they make news (Anderson) and movies (Bradley, Dominic). Instead of singing about wild horses, once upon a time, a Jagger owned or drove a team of packhorses, so he might have been a carter or peddler. The Blooms Orlando takes his last name from? Florists? Actually, the English surname Bloom more likely comes from the Middle English word blome, which was an ingot of iron, so Blooms were ironworkers.
So what about a Jackman? Someone who lifted heavy things by means of mechanical implements, right? Try a servant to someone named Jack. Jeremy Renner is a bit tougher, especially with his mixed European ancestry. But Renner may have come from an old Middle English or the Middle High German rennen, meaning “to run.” His namesake ancestor wouldn’t have been a track star, but probably a messenger of the mounted and military type.
Or you might need to know a foreign language. Leonardo DiCaprio might actually be Leonardo the Goat Herd in Italian. Or the name may not have anything to do with an occupation. It may have started as a nickname for an ancestor who looked like a goat.
Nah, couldn’t be.