Words change in our culture. Their dictionary or "official" meaning changes more slowly but popular perception of the word can change quite quickly sometimes.

An easy and dramatic example is "nine one one". Before Sept. 2001, most people in the US would interpret this phrase as the emergency number to dial in the event of a fire, medical, or police emergency. Since Sept. 11, 2001, it is often used to refer to the airplane attacks on the World Trade Center and Pentagon.

In Victorian times in England, it was extremely rude and improper in some segments of society to request a "thigh" or "leg" of chicken at a meal. These words were considered too suggestive to use, offensive to refined sensibilities. They were considered obscene.

Particular eddies of broader culture, certain sub-cultures, are rich in their own jargon. They generate new words or re-purpose older words to reinforce a group perspective, to create a barrier to entry from outsiders.

"Cool" used to describe a temperature, a perception of temperature, or an unemotional and calm demeanor. The post-WWII culture of the Beats (another interesting repurposing of a word) expanded on the calm and steady aspects of the word. From there, it moved into the anti-establishment movements of the 1960's. Eventually, the phone phreak/hacker culture and (I believe) hip-hop culture, with their penchant for phonetically respelling words, came up with "kewl," often used online today. (I have no scholarly sources for this; I'm just speaking off the top of my head.)

Words have power, make no mistake about it. Certain words can incite people to kill in some situations. It's not the words themselves; words also carry emotional weight and nuance beyond their literal interpretation. Words can trigger strong and intense emotions. It is difficult to predict how a word will be heard or acted upon.

If I say the word "Muslim" to a general, non-Muslim US audience, associative words immediately begin suggesting themselves. Given the recent past, many of those words will not have positive connotations. Most of these words will probably not be accurate in describing the majority of Muslims. This is part of the US verbal or linguistic zeitgeist at the moment.