Some English words appear to be similar but they have different meanings. Here are some of them:
Nullify / mollify
‘Nullify’ means ‘to officially state that something has no legal force.’
The election results were nullified because of voter fraud.
‘Mollify’ means ‘to make someone feel less angry and upset about something.’
The husband tried to mollify his wife.
Nutrition / nutritional
Food that is nutritious is full of the natural substances that your body needs to stay healthy or grow properly.
Brown bread is more nutritious than white bread.
‘Nutritional’ means ‘relating to the substances in food that help you to stay healthy.’
Cooking vegetables for too long lessens their nutritional value.
O / oh
The single ‘O’ is used only in religious, historic or poetic contexts. ‘Oh’ is the usual expression for mild surprise or pause.
O my luve’s like a red, red rose.
Oh, I see.
Objective / subjective
‘Objective’ means ‘based on facts, or making a decision that is based on facts rather than on your feelings or beliefs.’
It is hard to give an objective opinion about your own children.
A statement, report or attitude that is subjective is influenced by personal opinion and can therefore be unfair.
The ratings were based on the subjective judgment of one person.
Obligate / oblige
‘Obligate’ means ‘to make someone to do something because it is the law or the right thing to do.’
Tenants are obligated to pay their rent on time.
If you are obliged to do something, you have to do it because the situation, the law, or a duty makes it necessary.
Circumstances had obliged him to sell the house.
Obnoxious / noxious
‘Obnoxious’ means ‘very offensive, unpleasant or rude.’
“That’s an obnoxious idea,” he said.
‘Noxious’ means ‘harmful or poisonous.’
The factory was full of noxious fumes.
Observance / observation
‘Observance’ means ‘something you do as part of a ceremony, especially a religious ceremony.’
‘Observation’ is the process of watching something or someone carefully for a period of time.
The Army Commander’s orders were to keep the war prisoners under observation.
Obsolete / obsolescent
‘Obsolete’ means ‘no longer useful because something newer and better has been invented.’
Some laws become obsolete over the years.
‘Obsolescent’ means ‘becoming obsolete.’
Obviate / obliterate
‘Obviate’ means ‘to prevent or avoid a problem or the need to do something.’
The new treatment obviates the need for surgery.
‘Obliterate’ means ‘to destroy something completely so that nothing remains.’
Hiroshima was nearly obliterated by the atomic bomb.
Occupied / preoccupied
‘Occupied’ means ‘busy doing something.’
Thelma’s time was mostly occupied with her children.
‘Preoccupied’ means ‘thinking about something a lot, with the result that you do not pay attention to other things’
Ben is completely preoccupied with all the wedding preparations for his son.
Odious / odorous
‘Odious’ means ‘extremely unpleasant.’
An odious little man stood in front of me.
‘Odorous’ means ‘having a smell.’
Official / officious
‘Official’ means ‘approved or done by someone in authority, especially the government.’
There will be an official investigation into the causes of the explosion.
‘Officious’ means ‘too eager to tell people what to do, used to show disapproval.’
An officious traffic warden was on duty.
Onward / onwards
‘Onward’ means ‘moving forward or continuing.’
Are you happy with the onward march of science?
‘Onwards’ means ‘beginning at a particular time or age and continuing after that.’
Opportunity / chance
An opportunity is a chance to do something or an occasion when it is easy for you to do something.
I had a rare opportunity to go into the old palace.
‘Chance’ is the possibility that something will happen.
There is always the chance that something will go wrong.