List of commonly misused English words

This is a list of English words which are commonly misused. It is meant to include only words whose misuse is deprecated by most usage writers, editors, and other professional linguists of Standard English. It is possible that some of the meanings marked non-standard may pass into Standard English in the future, but at this time all of the following Non-standard phrases are likely to be marked as incorrect by English teachers or changed by editors if used in a work submitted for publication. Some of the examples are homonyms or pairs of similarly spelled words which are often confused.

N to R

novice and novitiate. A novice is a prospective or trainee member of a religious order. The novitiate is the state of being a novice, or the time for which one is a novice. However, a novice monk or nun is often incorrectly described as "a novitiate" (perhaps confused with "initiate").

of and have. In some dialects of spoken English, of and the contracted form of have, 've, sound alike. However, in standard written English, they are not interchangeable.
- Standard: Susan would have stopped to eat, but she was running late.
- Standard: You could have warned me!
- Non-standard: I should of known that the store would be closed. (Should be "I should've known")
overestimate and underestimate. There is frequent confusion between things that cannot and should not be over/underestimated, though the meanings are opposite.
- Standard: The damage caused by pollution cannot be overestimated (i.e. it is so enormous that no estimate, however high, is excessive)
- Standard: The damage caused by pollution should not be underestimated (i.e. it is wrong to regard it as minor)
- Non-standard: The damage caused by pollution cannot be underestimated (literal meaning: it is so minimal that no estimate is too small. Intended meaning: one of the previous two)

past and passed. Past refers to events that have previously occurred, while passed is the past tense of "to pass", whether in a congressional action or a physical occurrence.
- Standard: Congress passed the bill limiting the powers of the President.
- Standard: History is mainly concerned with the events of the past.
- Non-standard: He past my house on his way to the store.

peremptory and preemptive. A peremptory act or statement is absolute; it cannot be denied. A preemptive action is one taken before an adversary can act.
- Standard: He issued a peremptory order.
- Standard: Preemptive air strikes stopped the enemy from launching the new warship.

perpetrate and perpetuate. To perpetrate something is to commit it, while to perpetuate is something is to cause it to continue or to keep happening.
- Standard: The gang perpetrated outrages against several citizens.
- Standard: The stories only serve to perpetuate the legend that the house is haunted.

perquisite and prerequisite. Perquisite usually means 'an extra allowance or privilege'. Prerequisite means 'something required as a condition'.
- Standard: He had all the perquisites of a movie star, including a stand-in.
- Standard: Passing the examination was one of the prerequisites for a teaching position.

perspective and prospective. Perspective is a view with correct visual angles, example: parallel railway tracks converging in the distance. "Prospective" is a future possibility or expectation.

perspicuity and perspicacity. If something is perspicuous, it is easily understood; its meaning is obvious. If one is perspicacious, then one is quick to understand or has good insight.
- Standard: I admired her perspicacity; she just seemed to get it so much better than I.
- Standard: He expressed the idea so perspicuously that anyone could understand.
- Non-standard: She spoke in a perspicacious way.

peruse means "to read or examine very carefully" but is sometimes used erroneously when the exact opposite is meant: "to read superficially," "to glance over quickly," "to skim."

photogenic and photographic. The former is to be used to mean someone's likeness is particularly amenable to being well photographed. The latter is anything pertaining to photography whether it is technical e.g. photographic chemical or equipment, or generic e.g. photographic journals.

prescribe and proscribe. To prescribe something is to command or recommend it. To proscribe somebody or something is to outlaw him, her or it.

progeny and prodigy. Progeny are offspring or things that follow something else. A prodigy is a genius or a marvelous example of something.

Quartary and quaternary. Quartary (from Latin: quartarius) is the fourth member of an ordinal number word series beginning with (primary, secondary, tertiary) and continuing with (quintary, sextary, ...). Quaternary (from Latin: quaternarius) is the fourth member of a distributive number word series beginning with (singular, binary, ternary) and continuing with (quinary, senary, septenary, octonary ... centenary).

In biology, the non-standard usage "Quaternary structure" is so firmly entrenched that to refer to "Quartary structure" would be incorrect.

redundant does not mean "useless" or "unable to perform its function". It means that there is an excess of something, that something is "surplus to requirements" and no longer needed, or that it is obsolete.
- Standard: A new pill that will instantly cure any illness has made antibiotics redundant. (Antibiotics could still be used to cure illnesses, but they are no longer needed because a better pill has been invented)
- Standard: The week before Christmas, the company made seventy-five workers redundant.
- Non-standard: Over-use of antibiotics risks making them redundant. (This should read: over-use of antibiotics risks making them ineffective)

regimen and regiment. A regimen is a system of order, and may often refer to the systematic dosing of medication. A regiment is a military unit
- Standard: The sick soldier was removed from his regiment.
- Standard: The sick soldier was ordered to complete a regimen of amoxicillin.

reign and rein. A reign refers to the rule of a monarch. Reins are the straps used to control the movements of an animal (typically a horse). Thus, to "take the reins" means to assume control, and to have "free rein" means to be free of constraints.
- Non-standard: ...the Suns gave Sports Illustrated's Jack McCallum free reign of practices...
- Non-standard: Bobby Jindal, a whiz kid takes the reigns of Louisiana's Department of Health and Hospital