The speaker starts with a stubborn, slightly wry vow: they won't cut off their own head just to annoy an enemy. It's a joke about self-defeating protest, the kind of gesture that hurts you more than anyone else. From there the poem drifts through odd images of heads and feet. People pray for a "head with good countenance," a calm, pleasant, unremarkable mind, "ordinary as a horse." Yet a foot that stays ignorant, or a head that burns, seems to do about the same amount of good. Neither obedience nor dramatic sacrifice gets you very far.
The final lines turn toward something more hopeful. The speaker keeps their head and uses it, making "new words / of ash and trouble." Language becomes the form of resistance, built from damage and difficulty rather than from comfort. The mood is dry, defiant and a little dark, but there's a quiet energy in it. Survival, and the act of writing, is the point.