1. A trite or overused expression or idea.
2. A person or character whose behavior is predictable or superficial.
3. A trite or obvious remark.
4. Anything that has been overused before, or is being overused now, any word or phrase you remember being used a certain way more than once.
5. A time-worn expression which has lost its vitality and to some extent its original meaning.
Example: “Busy as bees”
Now, understand that without fail, using clichés in your poetry will serve no purpose other than to weaken it, to bore your reader into turning away.
To use clichés is to use someone else's words rather than your own. There is nothing original or creative about copying someone else. There's also nothing interesting about your results when you do so.