While it's not a traditional adjective or verb, you can sometimes use it in those ways:
* Adjective: In informal contexts, you might say something is "bantery," meaning it's characterized by banter. For example, "The atmosphere at the party was very bantery."
* Verb: You might use "banter" as a verb meaning to engage in banter. For example, "They bantered back and forth about the game."
However, these uses are not as common as using "banter" as a noun, and they might be considered more informal or colloquial.