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

sky pilot • skyman
sky pilot—
1
. a person licensed as a pilot: Hats off to these
sky pilots for providing yet another valuable forest manage-
ment tool. 2. (sl.) a priest; a military chaplain: At the mission
you would get a sermon, say 
1
5 minutes of religion from a sky
pilot.
skyman —(coll.) a paratrooper: During the days following
the drop … the sky men spearheaded the drive to capture the
city.
sleep it off • sleep on it
sleep it off —sleep until one is sober; sleep until one feels
normal: Shortly after he took off, he realized he had had too
much to drink and decided to pull over and sleep it off.
sleep on it—think about smth. for a while before coming up
with a decision: If you’re facing a problem you can’t get your
head around, you might be told to sleep on it.
sleep round the clock • sleep through the clock
sleep round the clock —sleep for twenty-four hours: The
climbers, when they returned, were so tired that they fell into
bed and slept round the clock.
Note: 
The expression does not correlate in meaning with the
phrase sleep around— have sexual relations with many people:
As far as I could discover, he had no reputation for sleeping
around.
sleep through the clock —fail to be woken by a clock: I’m
sorry I’m late, I slept through the clock this morning.
slip off • slip out
slip off —go away or leave quietly: Some say he’s slipped off,
to join his friend abroad.
slip out—
1
. = slip off: So I came downstairs without any
noise and slipped out. 2. (of news, information, etc.) leak out;
be revealed without intention: She did not identif y her
boyfriend at first but his name eventually slipped out in con-
versation.