Definition of "straining"

sundry violent gaspings and strainings

1851 November 14, Herman Melville, chapter 4, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley

Then after that process which Culverwel describes as so many strainings, refinings, and clarifyings, the mind is prepared for a true insight into the real nature of the world by way of intuition.

1931, John de Boer, The Theory of Knowledge of the Cambridge Platonists, page 64