1. Independent Clause: This is the more common meaning. An independent clause is a group of words that contains a subject and a verb and expresses a complete thought. It can stand alone as a sentence.
* Example: *The dog barked loudly.* (Subject: dog; verb: barked)
2. Phrase acting like an independent clause: This is less common, but it could happen in creative writing or non-standard language. Sometimes a phrase might be used to convey a complete thought, even though it doesn't technically have a subject and verb.
* Example: *No way!*, *Oh my goodness!*, *Good morning*. These are all phrases that express a complete thought, but they don't have a subject and verb.
To be sure of what "independent phrase" means in a specific context, you'll need more information.
* Where did you encounter this term? (In a book, a grammar exercise, a conversation?)
* What was the context? (What was being discussed?)
Once you have more context, it will be easier to determine what "independent phrase" means in that situation.