One Word Substitution
🔒 Log in to trackSuffix families: decode the word by its ending
🔒 Log in to trackIn one-word substitution you get a phrase and pick the single word for it. Many answer words are two parts: a root for the object and a suffix for the family. Learn the suffix and you can build the meaning of words you have not seen.
The question and the two-part idea
The question gives a phrase, such as the killing of a king. You pick one word: regicide.
Most such words have two parts.
- The root names the object: reg = king.
- The suffix names the family: -cide = killing.
Join them and you get the meaning without memorising the whole word.
Main families
| Suffix | Meaning | Examples |
|---|---|---|
| -cide | killing | regicide (king), fratricide (brother), patricide (father), infanticide (infant), genocide (a whole race), homicide (a human), suicide (oneself) |
| -phobia | abnormal fear | hydrophobia (water), acrophobia (heights), claustrophobia (closed spaces), xenophobia (foreigners), nyctophobia (darkness) |
| -ology | study of | ornithology (birds), entomology (insects), seismology (earthquakes), etymology (word origins), anthropology (humankind) |
| -graphy | writing, drawing | cartography (making maps), calligraphy (fine handwriting), demography (populations) |
| -phile | lover of | bibliophile (books), philatelist (stamps), anglophile (England) |
| -vorous | eating | herbivorous (plants), carnivorous (flesh), omnivorous (everything), insectivorous (insects) |
| -gamy | marriage | monogamy (one spouse), polygamy (several spouses), bigamy (a second marriage while still married), exogamy (outside one's group) |
Tip: Learn one family a day. Say each word with its object: "reg, king, regicide".
Roots that name the object
- reg king, frater brother, pater father, geno race.
- hydro water, acro height, xeno foreign, nycto night.
- ornitho bird, entomo insect, seismo earthquake, etymo word origin.
- biblio book, herb plant, carn flesh.
Example: Nyctophobia = nycto (night) + phobia (fear). It means fear of darkness.
Counting prefixes
These prefixes open many words.
| Prefix | Meaning |
|---|---|
| mono | one |
| bi, duo | two |
| tri | three |
| poly | many |
| pan, omni | all |
| semi, hemi | half |
| cent | hundred |
| milli | thousand |
Omnipotent (all-powerful), omniscient (all-knowing) and omnipresent (present everywhere) are one prefix plus one root each.
How the options are built
A question usually has one right word and three from the same or a nearby family.
- For study of insects, the options may all be -ology words. The root decides: entomology.
- For fear of heights, the options may come from different families. The suffix decides: -phobia.
Check both parts every time.
Look-alike pairs
- entomology (insects) and etymology (word origins).
- patricide (father), fratricide (brother), matricide (mother).
- philatelist (stamps) and numismatist (coins).
- -phobia (fear) and -phile (love).
- astronomy (science of stars) and astrology (predicting from stars).
Watch: Look-alike words differ by one letter group. Read the whole word.
Question types you will see
Each type: how to recognise it, the method step by step, and one question to try.
Killing words (-cide)
The phrase says 'killing of' or 'murder of' and names a victim: king, brother, father, mother, infant, race.
Spot the word 'killing' or 'murder'.
Note who is killed.
Match the root: reg = king, frater = brother, pater = father.
Add -cide and pick that option.
-cide is the killing suffix. The root names the victim.
The murder of a king is called: (a) homicide (b) regicide (c) suicide (d) genocide
Show solutionHide solution
Killing means -cide.
The victim is a king, so the root is reg.
Reg + cide is regicide.
(b) regicide
Fear words (-phobia)
The phrase says 'an abnormal fear of'.
Spot 'fear'.
Note the thing feared.
Match its root: hydro = water, acro = height, xeno = foreign, nycto = night.
Pick the -phobia word with that root.
-phobia is the fear suffix. The root names the thing feared.
An abnormal fear of heights: (a) claustrophobia (b) hydrophobia (c) acrophobia (d) xenophobia
Show solutionHide solution
Fear means -phobia.
Heights is acro.
Acrophobia.
(c) acrophobia
Study words (-ology)
The phrase says 'the study of' or 'the science of'.
Spot 'study'.
Note the thing studied.
Match its root: ornitho = birds, entomo = insects, seismo = earthquakes.
Check the look-alikes before you mark.
-ology is the study suffix. The root gives the subject.
The study of insects: (a) entomology (b) etymology (c) ornithology (d) seismology
Show solutionHide solution
Study means -ology.
Insects is entomo.
Etymology looks alike but means word origins.
(a) entomology
Lover, eater and marriage words
The phrase says 'a lover or collector of', 'feeding on', or describes a marriage practice.
Spot 'love', 'feeding' or 'marriage'.
Match the suffix: -phile, -vorous or -gamy.
Match the root for the object.
Pick the option with both parts.
Each suffix names a family, and the root names the object.
One who loves books: (a) bibliophile (b) philatelist (c) anglophile (d) philanthropist
Show solutionHide solution
Love means -phile.
Books is biblio.
Bibliophile. A philatelist loves stamps.
(a) bibliophile
Counting-prefix words
The phrase says 'all', 'many' or 'one' before the idea (all-powerful, all-knowing).
Find the counting idea: all, many, one, half.
Match the prefix: omni, poly, mono, semi.
Add the root for the rest of the meaning.
One prefix and one root build a whole family of words.
One who has power to do everything: (a) omniscient (b) omnipotent (c) omnipresent (d) omnivorous
Show solutionHide solution
All means omni.
Power is potent.
Omnipotent. Omniscient is all-knowing.
(b) omnipotent
Shortcuts that save time
Read the phrase and name the family (killing, fear, study). Then match the root. Two steps remove most options.
The study of earthquakes: (a) seismology (b) geology (c) zoology (d) etymology
Show solutionHide solution
Study means -ology.
Earthquakes is seismo.
Seismology.
(a) seismology
Rare words are often two parts joined. Nycto + phobia is fear of darkness. Entomo + logy is study of insects.
Write each look-alike pair on one card with the meaning of each word. Revise the cards every week.
Mistakes to avoid
Where most students lose marks on this subtopic.
Memorising each word alone.
Learn the suffix family and the root. Build the word from two parts.
Marking entomology for 'word origins'.
Entomology is insects. Etymology is word origins.
Mixing patricide, fratricide and matricide.
Father is pater, brother is frater, mother is mater. Check the victim.
Confusing -phobia (fear) with -phile (love).
Phobia means fear. Phile means love.
Marking a word after reading only its ending.
Check the root as well. Options often share the same suffix.
Quick revision
Read this the night before the exam.
-cide = killing, -phobia = fear, -ology = study, -graphy = writing, -phile = lover, -vorous = eating, -gamy = marriage.
Roots: reg king, frater brother, pater father, hydro water, acro height, xeno foreign, nycto night.
Omni = all: omnipotent, omniscient, omnipresent.
Family first, then root.
Look-alikes: entomology/etymology, patricide/fratricide, philatelist/numismatist.
Practice: 12 questions
Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.
Topic test · 12 questions
Suggested time 5 min · wrong answers go to your mistake notebook automatically.