Jettison comes
from Anglo-French geteson, which means literally "action of throwing"
and is related to the Latin verb jactare, meaning "to throw." The
noun jettison refers to a voluntary sacrifice of cargo to lighten a ship's load
in time of distress, and it is the source of the word jetsam (the name for
goods "jettisoned"); the word is often paired with flotsam
("floating wreckage"). These days you don't have to be on a sinking ship
to "jettison" something: the verb also means simply "to get rid
of."
Garble comes
from Anglo-French garbeler, meaning "to remove impurities or refuse from
(spices)." The English word refers to distortion of speech or writing that
makes its meaning unclear (impure).
Waffle is from
the Dutch wafel. Ultimately from the Indo-European root webh- (to weave; to
move quickly), which also gave us weave, webster, wave, waver, wafer, wobble,
and weft.
Intemperate means
"not well tempered"—in other words, not well mixed or balanced. The
word comes from Latin intemperatus, a combination of in- and the verb
temperare, meaning "to temper" or "to mix."
Opine is not a
back-formation of opinion. Both words come from Middle French opiner, meaning
"to express one's opinion," and Latin opīnārī, "to have in
mind" or "to think." And they were thought up as words for the
English language independently at different times.
Disheveled comes
from Middle English discheveled, meaning "bareheaded" or "with
disordered hair." That word is partially based on Anglo-French deschevelé,
a combination of the prefix des- ("dis-") and chevoil
("hair"). In English, disheveled describes things other than hair
that have a messy or untidy appearance.
Derring-do is a
quirky holdover from Middle English that came to occupy its present place in
the language by a series of mistakes and misunderstandings. In Middle English,
dorring don meant simply "daring to do." The phrase was misprinted as
derrynge do in a 15th-century work by poet John Lydgate, and Edmund Spenser
took it up from there. (A glossary to Spenser's work defined it as
"manhood and chevalrie.") Literary author Sir Walter Scott and others
brought the noun into modern use.