Cerebrate

Cerebrate: It sounds so much like celebrate that it’s often misheard and also rarely used. In fact, cerebrate means to use the mind or to think – because when you’re thinking, you’re using that part of your brain called the cerebrum.

Traduce

Traduce: Because it sounds so close to introduce – especially in pronunciation – it’s easy to think that this is a harmless word. In fact, to traduce someone is to speak ill of them or tell lies about them to damage their reputation – a far worse thing than just introducing them.

Abrosia

Abrosia: This is a strange word because it sounds too much like ambrosia – the name given to the supposed food and drink of the gods or absolutely heavenly food for mortals. But abrosia would be torture for someone expecting ambrosia, because abrosia means fasting or not consuming any food.

Lamprophony

Lamprophony (noun): Clear enunciation

There's no trace of lamps, pros, or phonies in this word's definition.  If you know that -phony means sound, you might guess that lamprophony is the sound of lampreys.  (Do they even make noise?) But no, lamprophony turns out to be a rather boring word that means clear enunciation.  (The Greek root lampro- means clear or distinct.)

Restive

Restive [adjective]: Restless or agitated.

Don't be fooled by the root word rest.  Rather than meaning restful, restive actually means restless. It can also mean disobediently stubborn or recalcitrant. This is a fine example of one of those sneaky words that means the opposite of what you may think it means.

Tortuous

Tortuous [adjective]: Twisting, having sudden or sharp turns and corners.

Because it sounds so much like torturous, most people confuse the two. While something can be torturous, it doesn't also mean that it's tortuous (or vice-versa). For instance, a book with many twists and turns can be tortuous, but quite an exciting and engaging read. A torturous book, on the other hand, is just unpleasant to read.

Fungible

Fungible: adjective: Replaceable of exchangeable for a similar item.

Though not as obscure as other strange English words, fungible looks deceptively like fungus and edible, which might put you in the mind of edible fungi. This word is actually an economic term meaning replaceable or exchangeable for another of its kind.  Currency is a fungible commodity; you can use any $20 bill to pay for a $20 item.