assuage

Definitions:

To soften; to mitigate; to allay; to soothe.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (verb) (v.) (verb)
To abate or subside.
- Newage Dictionary DB (verb) (v. i.) (verb intransitive)
Assuasive.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (verb) (v.) (verb)
To soften; to mitigate; to allay; to abate or subside.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (verb) (v.) (verb)
Assuagement.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (noun) (n.) (noun)
To soften, mitigate, or allay.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (verb) (v. t.) (verb transitive)
To soften or soothe; allay or lessen, as pain or grief; appease or pacify, as passion.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (verb) (v. t.) (verb transitive)
To alleviate; mitigate; allay.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (verb) (v. t.) (verb transitive)

Usage examples:

If the need of loving tormented his sentimental heart, he tried to assuage it in friendship.
- Saint Augustin by Louis Bertrand
The waves around the cliff's low base sprang high And madly dashed their spray in furious rage; The maid, howe'er, looked down with scornful eye, As if she could their mighty power assuage
- Love-or-Fame-and-Other-Poems by Sherrick, Fannie Isabel
But short as was the distance across the floor from the one door to the other, it gave me time to think again; to remember that this was Louis; and that whatever cause I had had to complain of him, whatever grounds to suspect that he was the tool of others, no friend could have done more to assuage my wrath, nor the most honest more to withhold me from entering on an impossible task.
- The Red Cockade by Stanley J. Weyman