Agroup of words that function together in a sentence, but don't include both subject and verb, is a

clause
connector
modifier
phrase

the answer is not a

I'm pretty sure it is phrase 

The answer might be a hope

Allusion and illusion. an allusion is an indirect reference, whereas an illusion is something that is unreal or incorrect. each of the nouns has a related verb form: allude “to refer indirectly to,” and illude (not a very common word), which may mean “to delude or deceive” or “to subject to an illusion.”