During proofreading I frequently come across the same words that have been confused time and again. I have already discussed words beginning A to C, now I will continue with words beginning with the letters D to F.

Deduce / deduct

To “deduce” something is to come to a logical conclusion or result, such as in “I deduced that he was telling a lie”. In contrast, to “deduct” is to subtract something, such as in “I deducted the service charge from the bill because of poor waiter service”.

Definite / definitive

These two words are often confused although they mean quite different things. “Definite” means exact or precise, as in “a definite distinction”, while “definitive” means conclusive or final, as in “a definitive game”.

Dissemble / disassemble

To “dissemble” means to conceal or pretend, as in to hide one’s true feelings. To “disassemble” means to take apart or dismantle.

Egoism / egotism

These words are frequently regarded as interchangeable but there are distinctions between them. “Egotism” is the more generally used term, meaning excessively conceited or self-absorbed, while in the strict sense “egoism” is a term used in the study of ethics for a theory treating self-interest as a foundation for moral behaviour.

Erupt / irrupt

The verb to “erupt” means to break or burst out, such as in “This long-dormant volcano has not erupted for over one hundred years”. To “irrupt” means to burst in or to violently enter, as in “The robbers irrupted the family’s Saturday night viewing a movie on TV”.

Fewer / less

“Fewer” refers to countable items, such as fewer people or fewer boxes of tomatoes, while “less” refers to bulk, uncountable items, such as in “She has less confidence than she used to have” or to singular nouns as in “He has one less apple than the others”. This is very like the difference between amount and number in part 1 of this series.

Fictional / fictitious

“Fictional” means “of fiction” and not factual, whereas “fictitious” means “false” or “not genuine”. However, the two words are interchangeable in the sense of imaginary or invented. Unsurprisingly, “fictional” is more frequently used with direct reference to literary works of fiction, such as novels and plays. “Fictitious” is usually reserved for deliberate intention to deceive.

Flounder / founder

The two verbs are often confused but are not related. To “flounder” is to act clumsily, move with difficulty or struggle. The noun flounder is also a fish. To “founder” means to break down, collapse, or sink (often in relation to a ship).

Formally / formerly

These are identical in pronunciation but have different meanings, with “formally” meaning “in a formal manner” as in formal dress. “Formerly” means “used to be” or “in the past”.