Wiktionary
phr. (context archaic English) To lessen, to subtract something from.
Usage examples of "abate of".
This poultice was scarce laid on, when the drummer, who had begun to abate of his exclamations, broke forth into such a hideous yell as made the whole company tremble, then, seizing a pewter pint pot that stood by him, squeezed the sides of it together, as if it had been made of pliant leather, grinding his teeth at the same time with a most horrible grin.
Though that young lady had brought her aunt into great good humour by those soothing methods which we have before related, she had not brought her in the least to abate of her zeal for the match with Lord Fellamar.
In the exercise of political government, he was compelled to abate of the stern rigor of fanaticism, to comply in some measure with the prejudices and passions of his followers, and to employ even the vices of mankind as the instruments of their salvation.
Just above this is another cascade of about 5 feet, above which the water, as far as I could see, began to abate of its velocity, and I therefore determined to ascend the hill behind me, which promised a fine prospect of the adjacent country.