adverse / averse
Adverse and averse are both turn-offs, but adverse is something harmful, and averse is a strong feeling of dislike. Rainstorms can cause adverse conditions, and many people are averse to rain.
affect / effect
Choosing between affect and effect can be scary. Think of Edgar Allen Poe and his RAVEN: Remember Affect Verb Effect Noun. You cannot affect the creepy poem by reading it, but you can enjoy the effect of a talking bird.
afflict / inflict
Both afflict and inflict cause pain, but afflict means to cause suffering or unhappiness, something a disease does, but inflict means to force pain or suffering, like if you smack someone upside the head.
allude / elude
Allude is coy, to allude is to refer to something in an indirect manner. But elude’s favourite thing to do is hide from the cops; it means to evade. Because the accent is on the second syllable in both words, it’s easy to get them mixed up.
allusion / illusion
Novelists, magicians, and other tricksters keep these words busy. Novelists love an allusion, an indirect reference to something like a secret treasure for the reader to find; magicians heart illusions, or fanciful fake-outs; but tricksters suffer from delusions, ideas that have no basis in reality.