Simply, poetry that has no distinct meter. The poet is free to turn the line at his or her discretion.
Perhaps they feel it a natural pause, perhaps for emphasis, perhaps they want to emulate a conversational style. It is largely up to you to decide if this works.
Let me here step aside and offer an example from that great pioneer of vers libre, Walt Whitman. Some things to note as you read: if you count the syllables of the lines you see no set meter, but Whitman is indeed using sentences to communicate to us his opinion.
I have said that the soul is not more than the body,
And I have said that the body is not more than the soul;
And nothing, not God, is greater to one than one’s self is,
And whoever walks a furlong without sympathy, walks to his own funeral, drest in his shroud,
And I or you, pocketless of a dime, may purchase the pick of the earth,
And to glance with an eye, or show a bean in its pod, confounds the learning of all times,
And there is no trade or employment but the young man following it may become a hero,
And there is no object so soft but it makes a hub for the wheel’d universe,
And I say to any man or woman, Let your soul stand cool and composed before a million universes.
And I say to mankind, Be not curious about God,
For I, who am curious about each, am not curious about God;
(No array of terms can say how much I am at peace about God, and about death.)
I hear and behold God in every object, yet understand God not in the least,
Nor do I understand who there can be more wonderful than myself.
Why should I wish to see God better than this day?
I see something of God each hour of the twenty-four, and each moment then;
In the faces of men and women I see God, and in my own face in the glass;
I find letters from God dropt in the street—and every one is sign’d by God’s name,
And I leave them where they are, for I know that wheresoe’er I go,
Others will punctually come forever and ever.
And as to you Death, and you bitter hug of mortality, it is idle to try to alarm me.
To his work without flinching the accoucheur comes;
I see the elder-hand, pressing, receiving, supporting;
I recline by the sills of the exquisite flexible doors,
And mark the outlet, and mark the relief and escape.
And as to you, Corpse, I think you are good manure—but that does not offend me;
I smell the white roses sweet-scented and growing,
I reach to the leafy lips—I reach to the polish’d breasts of melons.
And as to you Life, I reckon you are the leavings of many deaths;
(No doubt I have died myself ten thousand times before.)
I hear you whispering there, O stars of heaven;
O suns! O grass of graves! O perpetual transfers and promotions!
If you do not say anything, how can I say anything?
Of the turbid pool that lies in the autumn forest,
Of the moon that descends the steeps of the soughing twilight,
Toss, sparkles of day and dusk! toss on the black stems that decay in the muck!
Toss to the moaning gibberish of the dry limbs.
I ascend from the moon, I ascend from the night;
I perceive that the ghastly glimmer is noonday sunbeams reflected;
And debouch to the steady and central from the offspring great or small.
There is that in me—I do not know what it is—but I know it is in me.
Wrench’d and sweaty—calm and cool then my body becomes;
I sleep—I sleep long.
I do not know it—it is without name—it is a word unsaid;
It is not in any dictionary, utterance, symbol.
Something it swings on more than the earth I swing on;
To it the creation is the friend whose embracing awakes me.
Perhaps I might tell more. Outlines! I plead for my brothers and sisters.
Do you see, O my brothers and sisters?
It is not chaos or death—it is form, union, plan—it is eternal life—it is HAPPINESS.