(n.) something which hinders or troubles
There’s an old story that claims the word handicap derives from wounded soldiers returning home from war with injuries preventing them from returning to their day jobs, and leaving them with no option other than to beg on the streets, their caps literally held in their hands to catch the pennies of passers-by.
As ingenious a story as this is, it is of course completely untrue. (Not least because this would have likely given us the word “capihand” rather than handicap.) In fact the true origin of the word lies in an old method of trading goods called “hand-in-cap”, the origins of which date back as far as the fourteenth century at least.
Imagine there are two traders who want to exchange goods, but who are unsure about the relative value of the items they’re looking to swap. In a “hand-in-cap” trade, they would turn to a third party—essentially, a kind of umpire—who would take a look at the items up for exchange and assess their value. If he thought there were any kind of discrepancy between the two, he’d come up with a price (called the “odds”, or the “boot”) that the owner of the cheaper lot would then have to add into the exchange to make it fair.
Next, out comes the cap. The umpire, having given his assessment of the exchange, would then hold out his upturned cap. Both of the traders would take a few loose coins from their pockets, and go to drop them in it. If they agreed to the exchange, they’d drop their money into the cap, but if they didn’t, they’d keep it in their hands.
If both traders agreed, the exchange would go ahead as planned and the umpire would get to keep whatever change had been thrown in the cap as his fee. If neither of the traders agreed, the umpire would get nothing. And if only one agreed, he would get to retrieve his cash from the cap, the umpire would still get nothing, and no trade would go ahead.
Whatever the outcome, the umpire was always incentivised to come up with as fair exchange as possible, and the trade would only go ahead once everyone was happy.
So how does an obscure mediaeval trading system lead us to the word handicap as we have it today? Well, it was the idea of assessing the worth of something, just as the umpire did, that led to the idea of “handicap” horse races, in which an adjudicator is brought in to assess the quality of the horses taking part. Stronger horses would be laden down with weights to hamper their speed and make for a fairer race overall. And it’s this sense of something that hampers or encumbers an ordinary activity that we’ve retained in the language today.