It's Repetitive. And Redundant.
The loneliness includes me unawares.
And lonely as it is that loneliness
Will be more lonely ere it will be less (8-10, Frost; Desert Places)
I'm not sure if anyone else had it drilled into them to avoid repetition. Ironically, this advice was repeated over and over again. So, what's up with Frost? Did he miss those days in English class? The man repeats the word lonely (or variations of the word) four times in three lines. Loneliness...lonely....loneliness...lonely...And now the reader is starting to wonder if Frost perhaps feels lonely. Maybe a thesaurus could keep him company.
But before we're too hard on Frost, I'm going to lead you all down that lane that is named Memory and allow you to have a seat in my high school English class (you're welcome). We had been reading A Separate Peace, when Mrs. Karns, my favorite English teacher, pointed out a particular paragraph when Gene describes how Finny looks when he's sleeping. In the few lines the author uses to depict this scene, the word dead is repeated at least three times. Anyone who's read this book before will recognize that this paragraph is pretty blatant foreshadowing. My teacher explained that the constant lecturing against redundancy had its limits.
"Good writers can break the rules. It's not a crime to have the same word listed twice in a paragraph, but you have to have a reason for it. Not being able to think of another word is not a real reason.," Mrs. Karns hastened to add.
In this case, Frost was actually describing the word loneliness by using the word lonely. Generally this is no-no, but Frost uses the repetition to illustrate that the feeling is not going to get better, it's not going to vary in any way except to worsen.
**Aja talks about poets breaking the rules in a blog entry about Wordsworth