Regularly abused and misused! Uninterested means that you have no interest in something. ‘The budget t-shirt manufacturer is uninterested in breaking into the luxury goods segment of the market.’ Disinterested means that a party is independent. ‘Since the CEO stands to profit from the sale of the company, she cannot be considered a disinterested party in the current dispute.’
If a remark is ironic it conveys a meaning that is the opposite of its literal meaning. It does not mean ‘coincidental’. For example on a dull, rainy, windy day one might say, ‘What fabulous weather we’re having.’ This is irony. ‘This is the fourth time we’ve run into each other today. How ironic!’ is not irony.
Everyday is an adjective used to describe something that is used or encountered typically. ‘Tourists milling around in Old Town Square, viewing the sights through their camera lenses, is an everyday scene in Prague.’ Every day refers to something that happens day after day. ‘Every day the sound of birds wakes me at 5 am.’
Enormity means excessive wickedness or monstrous evil. If you talk about the ‘enormity of the issue’ you are not talking about its size. Enormous is very large (as in ‘An elephant is enormous when compared with a mouse.’
Noisome is not a word about noise. If something is noisome it is offensive to the senses, perhaps to the point of disgust (a noisome odour), or harmful (noisome fumes).
Discrete means having separate parts. ‘The paper is very long, but because it’s divided into discrete, clearly marked sections, it’s easy to find the results of the committee’s deliberations.’ Discreet means that someone is judicious in their conduct or speech. It’s often used in the context of keeping silent about a delicate matter. ‘I need you to be discreet about what you heard at today’s meeting because we don’t want the press getting hold of the information before we’ve told the staff.’