A dictionary of Confusable Phrases: More Than 10,000 Idioms and Collocations

Seven Days’ Battle, the • Seven Days’ Campaign,
the
Seven Days’ Battle, the —(U.S. hist.) the battle of James River
between the Federals and the Confederates in the American
Civil War: Three of the Ford brothers participated in the
“Seven Days’ Battle” in June 
1
862.
Seven Days’ Campaign, the —(hist.) the series of battles in
Bohemia concluding in the Battle of Sadowa (
1
866) in the
Austro-Prussian War: He served through the Seven Days
Campaign and was given an honorable discharge a year later.
sex something • sex up something
sex something —(of animals and plants) determine the sex by
anatomical examination: The specimen is not sexed, neither
is the sex noted on the drawing.
sex up something —(sl.) present smth. in a more interesting
or lively way (by introducing sex-oriented material): This film
took a classic story with lots of potential, put in many great
actors, gave them bad dialogue, sexed it up needlessly.
shadowy activities • shady activities
shadowy activities —activities about which little is known:
There was a report last month on the shadowy activities of the
Canadian Security Intelligence Service.
shady activities —activities that are dishonest or illegal: Amy
figures out that there is a link between the school’s closure
and Richard Packhouse’s shady activities.
shake a leg • shake a loose leg
shake a leg—(coll.) 
1
. move faster; hurry up: They are waiting
outside in the car; let’s shake a leg! 2. dance: The stage is ready
for them, if they like to act or the dancing-room, should they
wish to shake a leg.
Note:
The expression does not correlate in meaning with the
phrase swing the leg—(Nautical) evade duty: There was a nau-
tical expression “swing the leg,” an allusion to the pretence of
having a damaged leg so as to avoid work.
shake a loose leg —(rare) 
1
. = shake a leg 2: Play, for Heaven’s
sake, or you will work yourselves into a nation of automatons!
Shake a loose leg to a lively fiddle! 2. (coll.) lead an irregular
life; live freely: You’re too much occupied here with your shop:
besides, you may shake a loose leg yourself occasionally for all
the public knows, eh?