Everything in this short poem is described by what it lacks. The water has no reflections, the cellar has no dirt, and the speaker asks us to look at something that is "not me / nor the harbor." The title, "Absence," seems to name what runs underneath: someone or something that should be here and isn't.
The speaker's tone is calm, almost businesslike. They sit at "a good table" but eat only "one little dish at a time," which suggests a life that is comfortable on the surface yet thin and carefully rationed. The flat detail of "a Wednesday" adds to that feeling of an ordinary, unmarked day. Water that shows no image back gives the sense of someone who can't quite see themselves.
The mood is quiet, cool, and a little eerie. The poem never says what is missing, and that silence is the point. We feel the gap without being told its shape, much like the speaker does.