Why "hoist" in "Hoist with one's own petard"?

He was hoist with his own petard is one of my father's favorite phrases. As a child I had developed a vague understanding of the idiom in which petard was a kind of flag, which is why it was hoist, and being hoist by your own was an unpleasant fate bringing to mind captains being hung from their own ship's mast.

I now understand the meaning and origin of the phrase much better and know that a petard was a kind of early bomb and the idiom refers to being injured or killed by your own bomb. I am wondering about hoist though.

The Online Etymology Dictionary explains that in this expression, hoist is a past participle. What confuses me is the usage. We would not use hoist to describe being thrown by a bomb today, it brings to mind a controlled movement and does not carry any connotations of speed or violence, quite the contrary:

hoist
v. hoist·ed, hoist·ing, hoists v.tr.
1. To raise or haul up with or as if with the help of a mechanical apparatus. See Synonyms at lift.
2. To raise to one's mouth in order to drink: hoist a few beers. v.intr. To become raised or lifted.

My question is whether hoist used to have such a connotation. Since the phrase can be traced to Hamlet, was this poetic license or was the word commonly used to describe such violent movement at the time? Did to be hoist mean to die or be injured?

Solution 1:

Hoist is the past participle of the now-obsolete verb hoise. Hoise simply meant "to raise with effort or exertion". Today the verb hoist implies the use of ropes and some control, but that wasn't necessarily the case in Shakespeare's day. However, OED gives hoist with his own petard its own entry, which does indicate that Shakespeare coined this particular use.

1. trans. To raise aloft by means of a rope or pulley and tackle, or by other mechanical appliance.
a. orig. Naut., and chiefly to hoise sail; often with up.
b. to hoise out (forth): to launch, lower (a boat).
c. In other than nautical use. [For example, to hoyse up to a gibet. (1573)]
2. a. to raise aloft, lift up, usually with the notion of exertion.
b. hoist with his own petard (Shakespeare): Blown into the air by his own bomb; hence, injured or destroyed by his own device for the ruin of others.
3. To raise in position, degree or quality; to exalt, elevate; to raise in price.
4. To lift and move; to remove.

[OED]

Solution 2:

It's possible it's an idiom from the time. Remember that the phrase is over 400 years old. Looking in a dictionary today may not show the implied meaning as understood by people from that time.

But there are lots of things like that in English, and we use them without thinking.

Referring to something as being "cool" as an example. A really "cool" car. It's understood that it is not a literal reference to a car that is cold in temperature, but rather one that is desirable, or nice.

"Hoist" means to raise into the air, but looking back at the origin of the word "petar" in French it originally meant "to fart." Later it was applied to the breeching cannons "petards" which employed a small, closely placed explosive charge against a door or gate.

Shakespeare I think is having fun here, the audience would have understood the double meaning of the word. So he's making a joke of saying someone is blown, or launched into the air with their own fart. But also destroyed by their own explosive device.

I would also consider a medical possibility as well as social conventions of the time. I've read people in the past suffered terribly from regular bouts of upset stomachs, and with that I'd guess excessive flatulence owing to the extremely unsanitary conditions of their food supply.

As a result of this perhaps it wasn't considered bad form to expel gas loudly, and in public? And it's also possible that frequently resulted in an undesirable outcome.

So the play is more on the use of "petard" than it is "hoist."

Based on what you wrote - and I don't mean this as an insult - I think you're trying too hard to apply a literal definition of "hoist." The idea was implied, and understood by people of the time as a joke.

That we can't find a traceable basis for it today isn't surprising, as it is most likely 400 year old slang.

Solution 3:

In medieval times, castle gates were usually raised or “hoisted” by ropes and pulleys to allow passage. It seems logical to apply the term hoist to the wartime practice of making a passage through the gate with a petard, raising the gate by use of explosive force, so to speak.

Solution 4:

Hoist isn't especially sensible in terms of the metaphor of someone falling victim to their own explosive, over other options like "blown to bits" or maimed or merely killed, hurt or caught.

But it's worth considering the fuller context of the original use:

For 'tis the sport to have the enginer

Hoist with his own petar'; and 't shall go hard

But I will delve one yard below their mines

And blow them at the moon:

Shakespeare has Hamlet follow up this use with a related metaphor of undermining (as in the delve bit here, the mine bit here is mine as in bomb) them and then blowing them "at the moon". Hoist works better in his use of the petard metaphor, because he can then apply the same imagery of being propelled upward to a much greater extent in his next metaphor.

Indeed, if anything here the hoist serves mainly to build up to this "at the moon".

(It may also be because the fart pun is funnier that way as a good fart joke will go down well with some sections of the audience and the bit when you're using vivid metaphors about explosions sending people toward to moon is the place for them. That would explain Shakespeare's decision to drop the d, though it isn't clear to me that people often spoke about farts in French at the time).

Outside of this context, hoist is not as obvious a choice as others, and other figurative uses of petard tend to blow things open or tear them down, as often as upwards, especially since their tactical use was in breaching doors and gates:

Give but fire To this petarde, it shall blow open Madam The iron doores of a judge. — P. Massinger, Unnaturall Combat, 1639

His very name being a Petrard to make all the city-gates fly open. — T. Fuller, Holy State, 1642

Eternal Noise, and Scolding, The Conjugal Petard, that tears Down all Portcullices of Ears. — S. Butler Hudibras: Third Pt., 1678

And for this reason, it would not have been surprising if the phrase had been mutated to "blown up by his own petard" or something similar. But consider the next two citations of the expression's use after Shakespeare's that the OED has:

‘'Tis sport to have the engineer Hoist with his own petard’, as our immortal Shakspeare has it. — Scott Woodstock III. ix., 1858

To see the cruel bibliolater, in Hamlet's words, ‘hoist by his own petard’. — T. De Quincey Protestantism (rev. ed.) in Select. Grave & Gay VIII., 1858

These two both give their source and as such take greater pains to get the quotation right than they might have otherwise. And in bringing the original context to mind they help justify the relatively strange hoist. Indeed they likely do so (given that the phrase was not yet so well known as an expression) precisely because hoist makes so little sense out of context.

And around this time the expression "blown sky-high" came into use, while petards began to drop out of actual military use, making a verb for sending somebody upward more reasonable.

By the time George Eliot came to use it eight years later than De Quincey, it was apparently a phrase known (at least to the sort of people who read Eliot) and used as a unit, and so the unusual verb hoist that originally made sense only in the context of a subsequent metaphor, was now preserved with it. By now many people know petards only as something that hoists.