Common_Errors_in_English_usage

However, most civilians these days have never heard of "flak," so they
use "flack" instead, which originally meant "salesman" or "huckster."
You need to worry about this only if you're among old­time veterans.
You're more likely to embarrass yourself if you mix up the expression
"catch a lot of flak" with "give a lot of slack," which has almost the
opposite meaning. You can't catch slack.
FLAMMABLE/INFLAMMABLE
The prefix "in­" does not indicate negation here; it comes from the word
"inflame." "Flammable" and "inflammable" both mean "easy to catch on
fire"; but so many people misunderstand the latter term that it's better
to stick with "flammable" in safety warnings.
FLAUNT/FLOUT
To flaunt is to show off: you flaunt your new necklace by wearing it to
work. "Flout" has a more negative connotation; it means to treat with
contempt some rule or standard. The cliche is "to flout convention."
Flaunting may be in bad taste because it's ostentatious, but it is not a
violation of standards.
FLESH OUT/FLUSH OUT
To "flesh out" an idea is to give it substance, as a sculptor adds clay
flesh to a skeletal armature. To "flush out" a criminal is to drive him
or her out into the open. The latter term is derived from bird­hunting,
in which one flushes out a covey of quail. If you are trying to develop
something further, use "flesh"; but if you are trying to reveal
something hitherto concealed, use "flush."
FLOPPY DISK/HARD DISK
Floppy disks are fast disappearing from the computer world, but it's
been many years since they were literally floppy. The fact that a 3 1/2"
diskette is enclosed in a hard plastic case should not lead you to call
it a "hard disk." That's a high­capacity storage medium like the main
disk inside your computer on which your programs, operating system, and
data are stored.
FLOUNDER/FOUNDER
As a verb, "founder" means "to fill with water and sink." It is also
used metaphorically of various kinds of equally catastrophic failures.
In contrast, to flounder is to thrash about in the water (like a
flounder), struggling to stay alive. "Flounder" is also often used
metaphorically to indicate various sorts of desperate struggle. If
you're sunk, you've foundered. If you're still struggling, you're
floundering.
FLUKE
A fluke was originally a lucky stroke in billiards, and it still means a