Adverb
A word compounded of so and ever, used in composition with who, what, where, when, how, etc., and indicating any out of all possible or supposable persons, things, places, times, ways, etc. It is sometimes used separate from the pronoun or adverb.
Source: Webster's dictionaryHow selfish soever man may be supposed, there are evidently some principles in his nature, which interest him in the fortune of others, and render their happiness necessary to him, though he derives nothing from it except the pleasure of seeing it. Adam Smith
Only this incident inseparable every custom must have, viz., that it be consonant to reason; for how long soever it hath continued, if it be against reason, it is of no force in law. Edward Coke
In the woods too, a man casts off his years, as the snake his slough, and at what period soever of life, is always a child. In the woods, is perpetual youth. Ralph Waldo Emerson
Pray for me! and what noise soever ye hear, come not unto me, for nothing can rescue me. Christopher Marlowe
God grant indeed thy words are not for nought! Then shalt thou save me, since for many a day To such a dreadful life I have been brought: Nor will I spare with all my heart to pay What man soever takes my grief away; Ah! I will love thee, if thou lovest me But well enough my saviour now to be. William Morris
Like the winds that we come we know not whence and blow whither soever they list, the forces of society are derived from an obscure and distant origin. They arise before the date of philosophy, from the instincts, not the speculations of men. Adam Ferguson