I suffer from migraines. Bad ones. Sometimes, really, really bad ones. As a result, I’m always slightly affronted when people downgrade my affliction, linguistically and physiologically, to a niggle.

This has happened a few times, but the most irksome occasion of all was when I was admitted to hospital with the mother-of-all migraines. I had been experiencing excruciating pain above the eyes. In addition, I was extremely intolerant to light, sound and smell and had been vomiting for two days.

The triage nurse seemed perplexed that I had come in with a mere pain in the head and proceeded to question me, with overt bemusement, about my headache.

Let it be clear to anyone in doubt, a headache is a mild pain, located in the head, over the eyes or at the temples. In contrast, a migraine is a volcanic eruption inside your skull or a platoon of soldiers in hobnail boots doing marching drills inside your head.

<alt="fiery explosion of colour">

What are synonyms?

This circuitous introduction leads perfectly into a discussion about synonyms. The word synonym comes from two Greek words – the prefix syn– means “together” and the suffix –onym means “name”. So, synonyms are words that name the same thing. Put another way, synonyms are words that have the same or nearly the same, not identical, meaning as other words or expressions.


  • cap/hat   
  • clever/intelligent      
  • funny/strange         
  • funny/amusing
  • specimen/example
  • template/blueprint/pattern
  • opportunity/chance
  • gather/collect

Why do we use synonyms?

We use synonyms for creative effect – to jazz up our speech and writing and to avoid having to repeat the same words over and over again. How boring would that be!

Context is key

If we revisit my initial comparison between migraines and headaches, it becomes clear that although the two terms are synonymous, context is everything.

All words have synonyms, but not all synonyms are interchangeable in all contexts.

Overlapping meaning

Synonyms are never exactly the same, but there is generally an overlap of meaning.

The diagram below identified elements of meaning of the words, nerd, dork and geek. There are aspects of meaning that are common to all three words, but there are others that are unique to specific words only.

alt="three overlapping circles with word meanings written in each">

For instance, the notions of obsessiveness, extreme intelligence and  social ineptitude are common to all three words, but the clumsiness and silliness inherent in dork are not necessarily shared by geek and nerd.

How to choose the best synonyms

When it comes to replacing one word with another, go for the best fit.

Find the best match

  • When choosing a synonym, replace it with the best match because word meanings often differ by degrees. Think, for example, of the following words: watch, see, look, glance, gaze, stare and gawk. They  all convey a slightly different sense of the act of looking or seeing. So, for instance, we would watch a soccer match, but not glance or gawk at it.

Use words from the same part of speech

  • Synonyms can be from any part of speech. However, the new word must belong to the same part of speech as the word it is replacing.
    • For instance, we might replace awesome with adjectives such as incredible, astonishing or amazing, but never with the verb, amazed.
    • We might replace the noun, car, with other nouns such as auto, automobile, and motorcar. 
    • The verb participate can be replaced with the verbs, take part, compete, enter and  join.
    • The adverb quickly can be replaced with fast, promptly and rapidly.
    • Similarly, the prepositions on and upon can be used more or less interchangeably.

Maintain the meaning of the original context

  • When replacing a word with its synonym, maintain the meaning of the original sentence.


A thesaurus might list the following synonyms for senior:
elder, older, high-ranking, chief, superior, top, last, final.

  • However, in the sentence:
              Jemima is in her senior year at university,
    senior cannot be replaced with elder, older, high-ranking, chief, superior or top because the meaning will change and it will become nonsensical. 
  • If senior is replaced with either last or final, the meaning of the original will remain unchanged.

Match the connotative meaning

The denotative meaning of a word relates to its dictionary definition.  By contrast, connotation refers to the additional meaning or baggage that the word carries, which can be either positive, negative or neutral. (See

When replacing a word with a synonym, make sure that the replacement word has the same connotative meaning as the original. It should not carry any additional connotative baggage, which would be inappropriate in the given context.


A thesaurus might list the following synonyms for buttocks:

backside, butt, bottom, behind, seat, rump, rear, rear endcheeks, hindquarters, tush, ass, arse, posterior, bum

Let’s imagine that the following sentence is used in a medical or anatomy text:

The gluteus maximus muscle is located in the buttocks and is regarded as one of the strongest muscles in the human body.

In this instance, it would be inappropriate to replace buttocks with the options given, particularly words such as bum, checks, tush, ass or arse because of the negative and derogatory connotations they carry. Buttocks is a neutral physiological term that describes part of the human anatomy. 

If, however, we want to replace the word arse in the sentence:    

Simon is so troublesome; he is such a pain in the arse

we would probably use words such as butt or backside, which are slightly more colloquial, everyday terms, with similar negative connotations to the word being replaced.