All these terms are used in reference to a word or expression except for diction that refers to a way of pronouncing.
1. Manner of expressing ideas in words: diction
2. Worn out by use: trite
3. Words or phrases usually characterized by a special vividness or coloring: slang
4. Used in everyday, informal talk, but not in formal English : colloquial
5. Stiffly dignified or formal: stilted
6. Not definitely or precisely expressed :vague