The title, "Walking it off," tells us the speaker is trying to shake off a bad mood, and the first stanza hints at what it was. They admit to arguing hard "with little reason," pretending to know things without being sure whether they really do. It's an honest, slightly embarrassed confession, the kind we make once the heat has passed and we see how thin our certainty was.
The second stanza shifts into the woods, and the tone softens. Something barely audible, "a word too low to hear," goes along with the speaker. The poem never says what the word is, which suits its quiet mood. Then comes the image of "a cool furniture of air," an odd, lovely phrase that makes the air feel like something solid and calming, almost like a room you can settle into.
Overall, the poem moves from restless self-doubt to a gentler stillness. The speaker doesn't resolve anything, but being outdoors seems to ease the need to be right.