Without context, words are only a mere skeleton of an idea. It is context that fleshes out true concept and motive. Context allows us use of homographs (words that have the same spelling, but different meaning), homophones (words that are pronounced the same as another word, but has a different meaning), heteronyms (words that are identical in spelling, but have different pronunciation and meaning), homonyms (words that have the same spelling and the same pronunciation but have different meanings), polysemes (words with multiple, related meanings), and capitonyms (words that change in meaning, and sometimes pronunciation, when capitalized).
Once we develop proper sentence context, there is additionally situational context. I remember learning, when I was five, that it was okay to tell my grandmother that I thought Aunt Peggy was fat, and the issue was discussed somewhat extensively (for a five year old) However, alerting her to this fact myself, I learned, was not the most proper thing a young lady should do.