What is it called when a word has a negative connotation?

Any Word which suggests something unpleasant as opposed to pleasant, evil as opposed to good, destructive as opposed to constructive. The positive connotations of "As she walked into the room, I immediately noticed her windblown hair, her scent, her trilling voice" can be made negative if you say "As she walked into the room, I immediately noticed her messy hair, her smell, her squeaking voice . . ."