I Knew a Woman Summary
In the first stanza, the speaker describes the beauty of the woman he loves. Her beauty, he says, goes far deeper than her skin; it goes all the way down to her bones. She is like a lovely creature from nature, akin to a beautiful bird, and she evidently feels some kinship and sympathy with them. Even her physical movements are beautiful: perhaps she is especially graceful and moves her body in interesting and unexpected ways. She also has a number of noteworthy virtues, so "choice" that he feels only the gods could speak to them, though he concedes that English poets who have been raised on stories and myths of the ancient Greeks could manage it.
In the second stanza, he describes how he longs to give her all she wishes for, and they evidently have had a very successful and fulfilling sexual relationship. She has "stroked" him and taught him quite a bit with her "undulant" skin. He seems to feel like an animal that she can be kind to or command, and he will "nibble meekly" from her hand and follow her in all things.
The third stanza, to me, is the most abstract. References to nature, to her "full lips" and her "flowing knees" and "several parts," seem to suggest more sexual activity. There is some contrast between the highly sexual nature of the descriptions of this woman and her simultaneous "pure repose." He describes her "quiver[ing]" or perhaps his own as well as her circular movement that makes her seem sort of earthly and cosmic at the same time.
In the fourth and final stanza, the speaker describes the making of "hay," a common idiom refers to seizing the day and making the most of one's time. He asks, "But who would count eternity in days?" suggesting that though he knows that they will be together forever, he still wants to enjoy every single day, every single moment, with her because of the complexity of her "wanton ways." He says he now measures time "by how a body sways" rather than by hours or minutes. She, specifically the movements of her body, is how he keeps track of time.