“Opening on a frozen lake”

One of 843 in New York's 50-Across

Sprinkle with oil, say

Sister's commitments

Foreign exchange?

Essayist who wrote "If you wrest my words beyond their fair construction, it is you, and not I, that are the April Fool"

End of a set, in mathematics

Howard who wrote "A People's History of the United States"

Eagle pose, for one

Smooths