In Hamlet 1.4.77 and following, the Prince of Denmark encounters the ghost of his murdered father, a spectral figure beckoning him onward to a more secluded battlement of Elsinore Castle.  Fearing what might happen, the Prince’s friends try to intervene (“You shall not go, my lord!”), at which point Hamlet, drawing his sword, for once taking decisive action, cries out

                        By heaven, I’ll make a ghost of him who lets me!

There’s a pleasing wit in these two lines. Hamlet plays with the word “ghost” even as he’s genuinely terrified by the specter looming before him.  But the puzzling word in the passage is “lets.”  In a context clearly calling for the sense “prevents”—essentially, Hamlet is saying “I’ll kill anybody who gets in my way”—we find a word with what looks like the opposite meaning, “allows,” “gives permission.”

The solution to the puzzle lies in the history of the word.  Once upon a time, in Shakespeare’s time in fact, and for centuries before that, “let” did mean “hinder” or “prevent”; this sense derived from the Old English verb lettan.  Over the centuries the word was taken over by “let” in the sense “allow,” which derives from the Old English verb lætan.  In contemporary usage the word has lost the “prevent” sense, except in two highly specialized contexts—the law, where we find the set phrase “without let or hindrance,” and an equally competitive activity, tennis.  When you serve the ball and it hits the net cord before toppling into the far court, someone calls out “Let!” and you serve again.  Nowadays people tend to say “Net!,” and you can see why they do.  “Net!” makes immediate sense whereas “Let!” does not.  But to me the latter word seems worth preserving, as being pleasingly old-fashioned.

Hamlet was not a tennis player, as far as we know.  His sport was fencing.  Still, he might have known the tennis usage of “let,” and come to think of it that tennis ball caroming off the net cord, hanging indecisively in the air for the moment (will it bounce backward and score a fault? will it bounce forward and permit another serve?) isn’t a bad image for the Prince of Denmark himself, hesitating, temporizing, delaying.  There’s a lovely image of a Hamlet-like tennis ball in Woody Allen’s film Match Play:

Meanwhile, films and stage productions of Hamlet have to decide how they are going to handle “By heaven, I’ll make a ghost of him who lets me!”  A recent Royal National Theatre production, directed by Nicholas Hytner and screened in HD in cinemas around the world, changed the line to “By heaven I’ll make a ghost of him who bars me.” Gregory Doran’s equally recent Royal Shakespeare Company version, starring the Dr Who alumnus David Tennant, kept the original line intact.  “Bars” may be more intelligible, but it lacks the history of “lets”—a word which in its quaint precision harks back to the endlessly inventive Renaissance that gave birth to both Shakespeare and tennis.