(See also PACE, SPEEDING.)

at the drop of a hat At the slightest provocation; at once, promptly, without delay; immediately, instantly. In use since at least 1854, this expression is said to have derived from the early American frontier custom of dropping a hat to signal the beginning of a fight. The downward sweep of a hat has also been used to signal the start of races.

before you can say “Jack Robinson” Instantly, immediately. There are two common but equally unsubstantiated theories as to the origin of this phrase. One holds that a rather mercurial gentleman of that name was in the habit of paying such brief visits to neighbors that he was gone almost as soon as he had been announced. The other sees the source in these lines from an old, unnamed play:

In popular use during the 18th century, the expression appeared in Fanny Bur-ney’s Evelina in 1778.

before you can say “knife” Very quickly or suddenly; before you can turn around. This colloquial British expression is equivalent to before you can say “Jack Robinson.” Mrs. Louisa Parr used it in Adam and Eve (1880).

in a jiffy In a trice, in a minute, right away. Although the exact origin of this expression is unknown, it is thought by some to be the modern spelling of the earlier gliff’a glimpse, a glance,’ and by extension ‘a short space of time, a moment.’ The phrase dates from the late 18th century.

in a pig’s whisper In a short time; soon. A pig’s whisper was originally a short grunt, one so brief that it sounded almost like a whisper.

in two shakes of a lamb’s tail Immediately, right away; instantly. Although the exact origin is unknown, this expression is thought by some to be an enlargement of the older phrase in a brace or couple of shakes, which appeared in Richard H. Barham’s The In-goldsby Legends (1840). However, anyone familiar with sheep knows the quivering suddenness with which those animals twitch their tails.

one fell swoop All at once; with a single blow or stroke. The swoop of the phrase may carry its obsolete meaning of ‘blow,’ or refer to the sudden descent of a bird of prey; fell carries its meanings of ‘fierce, savage, destructive.’ Macduff uses the phrase in Shakespeare’s Macbeth when he learns that his wife, children, and servants have all been killed. In doing so, he plays on its associations with birds of prey:

Contemporary usage does not restrict the phrase to serious contexts of fatal destruction; in fact, the expression is so often used lightly that it has generated the common spoonerism one swell foop.

on the double Instantly; without delay; right off the bat. This expression originated as military jargon for double-time marching. The term’s current civilian use is commonplace in the United States.

p.d.q. Immediately, at once. This widely used abbreviation of “pretty damn quick” was coined in 1867 by Don Maginnis, a Boston comedian.

right off the bat Immediately; at once; instantaneously. This very common expression is of obvious baseball origin.

The less frequently heard synonymous right off the reel may derive from the specific sports use of reel in fishing, though many of the more general uses of reel could account equally well for its origin.