What is a group of words called that has neither subject nor verb?

A group of words that has neither subject nor verb is called a phrase.

Here are some examples of phrases:

* Prepositional phrase: "in the garden"

* Noun phrase: "the big red ball"

* Adjective phrase: "very happy"

* Verb phrase: "will be playing"

Phrases can be used as parts of sentences, but they cannot stand alone as complete sentences.