"Terpsichorean" is a word that arrives in a toga. It comes from Terpsichore, the Greek Muse of dance, and means simply "to do with dancing." It is rarely used without a wink, usually when someone wants to describe clumsy footwork in grand terms. Dave Bonta sets this ornate title above three plain lines about a bad foot and a reflection, so the joke is already under way before the poem starts: something lofty is about to be brought down to the size of a drinking glass.
The scene is easy to picture. Someone sits with a glass, perhaps of water or wine, and the moon is caught in its surface, trembling. The poem never says what "glass" means, and it could just as well be a mirror or a windowpane. A glass of liquid seems the most natural reading, because only liquid would make the moon dance. The central idea comes from the link the poem hints at between the dancing image and the "crooked foot." If the speaker's foot is what jolts the table or the floor, then the awkward body is what makes the reflection move. The speaker cannot dance, and the moon dances anyway because of that failure.
Whose anger is it, though? The poem has no punctuation and no capital letters, so "angry at my crooked foot" floats free at the front of the sentence. It can attach to the moon, as in "the dancing moon, angry at my crooked foot, in my glass," so that the moon stamps and flickers in annoyance at the clumsy speaker. Or it can belong to the speaker, who is furious at their own foot and watches the moon's dance as if it were a taunt. Probably the poem wants both. The moon's "anger" may be what a frustrated person sees in a quivering reflection, with their own mood projected onto the sky. Personification and self-reproach run together here, and the missing punctuation lets them.
"Foot" is also a poet's word, since a metrical foot is the basic unit of rhythm in verse. The poem never says so, but judging by the title's talk of dance and the poem's own uneven lines, the "crooked foot" may be a small joke about verse that won't walk straight. That reading is an inference, but it fits a poem so interested in movement and so unsteady in its own gait.
The construction is a quiet piece of craft. The lines taper: six syllables, then four, then three. The stresses fall away too, three in the first line (ANgry at my CROOKed FOOT), two in the second (the DANCing MOON), and one in the last (in my GLASS). The poem narrows toward its final image. The vast, distant moon is squeezed into something that fits in a hand, and the last word, "glass," shuts with a hard, brittle click like a lid. Hard sounds recur in "crooked" and "glass," while "angry" and "dancing" begin with the same "an" sound, so the emotion and the movement feel like one motion. "Foot" and "moon" share their "oo" spelling and a similar vowel, which makes a faint echo where a rhyme might have been. There is no real rhyme, and the poem simply stops rather than clicking shut. The repeated "my," in "my crooked foot" and "my glass," keeps everything at human scale, with the body at one end and the vessel at the other.
What makes the poem significant is how much it gets out of so little. It is about haiku-length, though it ignores the 5-7-5 pattern, and it has the single-image focus of that tradition. In three lines it manages comedy, self-mockery and a little tenderness. The moon is usually a cold, remote object of grand feeling, and here it becomes a dance partner, or perhaps a critic, trapped in a glass and set moving by an embarrassing foot. A flaw in the body, which the speaker is ashamed of, produces the only dance in the poem. The poem doesn't tell us whether to laugh or sympathise, and it keeps both possibilities open.