Irony
What people think it means: funny or unfortunate
What it actually means: the use of words to convey a meaning that is the opposite of its literal meaning
Travesty
What people think it means: a tragedy
What it actually means: a grotesque or debased likeness or imitation, a mockery
Bemused
What people think it means: amused
What it actually means: bewildered or confused
Enormity
What people think it means: huge
What it actually means: outrageous or heinous character; atrociousness
Effect
What people think it means: to cause something to change
What it actually means: something that is produced by an agency or cause; result; consequence
Disinterested
What people think it means: bored
What it actually means: unbiased by personal interest or advantage; not influenced by selfish motives, indifferent
Irregardless
What people think it means: regardless
What it actually means: nothing, it's not a word.
i.e.
What people think it means: for example
What it actually means: that is; in other words
Fortuitous
What people think it means: lucky
What it actually means: happening or produced by chance; accidental
Plethora
What people think it means: a lot of something
What it actually means: overabundance; excess; more than is needed
Inflammable
What people think it means: fireproof
What it actually means: capable of being set on fire; combustible; flammable
Infamous
What people think it means: famous
What it actually means: having an extremely bad reputation
Adverse
What people think it means: opposed to, averse
What it actually means: unfavorable or antagonistic in purpose or effect
Clichéd
What people think it means: overdone
What it actually means: nothing, it's not a word. "Cliché" is a noun.
Dichotomy
What people think it means: difference
What it actually means: division into two mutually exclusive, opposed, or contradictory groups
Hone
What people think it means: to converge upon or approach
What it actually means: to make more acute or effective; improve; perfect
Random
What people think it means: funny, silly
What it actually means: proceeding, made, or occurring without definite aim, reason, or pattern
Dilemma
What people think it means: a problem
What it actually means: a situation requiring a choice between equally undesirable alternatives
Less
What people think it means: comparing numbers of countable items
What it actually means: a smaller extent, amount, or degree of singular mass nouns
Refute
What people think it means: to reply or deny
What it actually means : to prove to be false or erroneous, as an opinion or charge