intransitive verb
Definition: To experience a sensation on the skin that makes you want to scratch.
Example: After playing in the grass, I started to itch all over.
noun
Definition: A feeling on the skin that makes you want to scratch, often caused by irritation or a skin condition.
Example: After playing in the grass, I felt an itch on my arm.
transitive verb
Definition: To make a part of the body feel a tingling sensation that makes you want to scratch it.
Example: The mosquito bite made my arm itch.