Nothing can damage your ethos more quickly than a glaring misuse of language. Mistakes in grammar or word selection can be disastrous because most audiences attribute such errors to incompetence. They are likely to reason that anyone who misuses language can hardly offer good advice. When you select your words, be careful that they say exactly what you mean to say.
Occasionally beginning speakers, wishing to impress people with the size of their vocabularies, get caught up in the “thesaurus syndrome.” They will look up a simple word to find a synonym that sounds more impressive or sophisticated. What they may not realize is that tl’ie words shown as synonyrn.s often have slightly different meanings. For example, the words “disorganize” and “derange” are sometimes listed as synonyms. But if you refer to a disorganized person as “deranged,” you will see what we mean.
People often err by using words that sound similar to the word they want. Such confusions are called malapropisms, after Mrs. Malaprop, a character in an eighteenth-century play by Richard Sheridan. She would say, “He is the very pineapple of politeness,” when she meant pinnacle. Thus a major league baseball player trying to explain why he had forgotten a talk show interview, said: “I must have had ambrosia” (which probably caused his amnesia, which is what he apparently meant). Archie Bunker in All in the Family was prone to malapropisms, such as “Don’t let your imagination run rancid” when he meant rampant. William J. Crocker of Armidale College in New South Wales, Australia, collected the following malapropisms from student speeches in his classes:
A speaker can add interest to his talk with an antidote. [anecdote]
Disagreements can arise from an unintended conception. [Indeed they can!]
The speaker hopes to arouse apathy in his audience. [sympathy? empathy?]
Good language can be reinforced by good gestation. [gestures]
The speaker can use either an inductive or a seductive approach.36 [deductive]
Students, ballplayers, and fictional characters are not the only ones who make such blunders. A reporter once praised an attorney for his ability to dissemble a bicycle. As a colleague observed with heavy irony, no doubt the man could “dissemble”—after all, he was a lawyer. But “dissemble” means to conceal and deceive, often by talking around a point. What the unfortunate reporter was praising was the lawyer’s ability to “disassemble” the bicycle. Elected officials are also not above an occasional malapropism. One former United States senator declared that he would oppose to his last ounce of energy any effort to build a “nuclear waste suppository” [repository] in his state.38 And the Speaker of the Texas legislature once acknowledged an award by saying, “I am filled with humidity” (perhaps he meant moist hot air as well as humility).

The lesson is clear: To avoid being unintentionally humorous, use a current dictionary to check the meaning and pronunciation of any word you feel uncertain about.