Some English words appear to be similar but they have different meanings. Here are some of them.
Inflammable / flammable
‘Inflammable’ materials or substances will start to burn very easily.
Petrol is highly inflammable.
Something that is ‘flammable’ burns easily.
Caution! Highly flammable liquid
‘Inflammable’ and ‘flammable’ are synonyms.
Informant / informer
An ‘informant’ is someone who secretly gives the police or the army information about someone else.
One of the witnesses was a paid informant for the police.
An ‘informer’ is someone who secretly tells the police or the army about criminal activities, especially for money.
‘Informant’ and ‘informer’ are synonyms.
Ingenious / ingenuous
An ‘ingenious’ plan, idea or object works well and is the result of clever thinking and new ideas.
Many animals have ingenious ways of protecting their young.
An ‘ingenuous’ person is simple, trusting, and honest, especially because they have not had much experience of life.
Inoculate / vaccinate
‘Inoculate’ means to protect someone against a disease by putting a weak form of the disease into their body using a needle.
Children have to be inoculated against hepatitis.
‘Vaccinate’ means ‘to protect a person or animal from a disease by giving them a vaccine.’
Children should be vaccinated against measles.
‘Inoculate’ and ‘vaccinate’ are synonyms.
Insolvent / bankrupt
‘Insolvent’ means ‘not having enough money to pay what you owe.’
The company was declared insolvent.
‘Bankrupt’ means ‘without enough money to pay what you owe.’
The firm went bankrupt.
‘Insolvent’ and ‘bankrupt’ are synonyms.
Instantly / instantaneous
‘Instantly’ means ‘immediately.’
All the accident victims died instantly.
‘Instantaneous’ means ‘happening immediately.’
Today, we have instantaneous methods of communication.
‘Instantly’ and ‘instantaneous’ are synonyms.
Instinct / intuition
‘Instinct’ means ‘a natural tendency to behave in a particular way or a natural ability to know something which is not learned.’
Animals have a natural instinct for survival.
‘Intuition’ means ‘the ability to understand or to know something because of a feeling rather than by considering the facts.’
Intuition told her it was unwise to argue.
‘Instinct’ and ‘intuition’ are synonyms.
Institute / institution
An institute is an organisation that has a particular purpose such as scientific or educational work, or the building where this organisation is based.
Tom works at the Tea Research Institute.
An institution is a large organisation that has a particular kind of work or purpose.
The World Bank is a powerful institution.
‘Institute’ and ‘institution’ are synonyms.
Intense / intensive
‘Intense’ means ‘having a very strong effect or felt very strongly.’
Young people are under intense pressure to succeed in their academic activities.
‘Intensive’ means ‘involving a lot of activity, effort or careful attention in a short period of time.’
We followed a three-month intensive course in English at the university.
Independence / interdependence
‘Independence’ means ‘political freedom from control by the Government of another country.
Sri Lanka gained independence from Britain in 1948.
‘Interdependence’ means ‘a situation in which people or things depend on each other.’
Internment / interment
‘Internment’ means ‘detaining and confining someone, usually for security reasons, during a conflict or war.’ An ‘interment’ is a burial.