• Webster's Revised Unabridged Dictionary
    • a Soothfast Firmly fixed in, or founded upon, the thruth; true; genuine; real; also, truthful; faithful. "In very soothfastness.""Why do not you . . . bear leal and soothfast evidence in her behalf, as ye may with a clear conscience!"
    • adv Soothfast Soothly; really; in fact. "I care not if the pomps you show
      Be what they soothfast appear."
    • ***
Century Dictionary and Cyclopedia
    • soothfast Truthful; veracious; honest.
    • soothfast True; veritable; worthy of belief.
    • soothfast Veritable; certain; real.
    • soothfast Faithful; loyal; steadfast.
    • ***
Chambers's Twentieth Century Dictionary
    • adj Soothfast truthful, honest, faithful
    • ***


Webster's Revised Unabridged Dictionary
Sooth, + fast, that is, fast or firm with respect to truth
Chambers's Twentieth Century Dictionary
A.S. sóth, true; Ice. sannr, true.


In literature:

Gladsome to me, O my life, this love whose offer thou deignest Between us twain lively and lusty to last soothfast.
"The Carmina of Caius Valerius Catullus" by Caius Valerius Catullus
But, if I were to come, wad ye really and soothfastly pay me the siller?
"The Best of the World's Classics, Vol. V (of X) - Great Britain and Ireland III" by Various

In poetry:

Lord Hafbur mid his longing sore
Down on the bed he sat:
I tell you of my soothfastness,
His byrny clashed thereat.
"Hafbur And Signy" by William Morris