adj (archaic) Genuinely true or real.
- I'll take your word for it,” said he, with another glance at a very soothfast mask that came down on as sweet a pair of lips as ever man took craving for.
— Neil Munro, Brian D. Osborne (2022)
- And hereby mayest thou see and learn, that there is no soothfast security, nor yet no true rest in this life.
— Evelyn Underhill, The Cloud of Unknowing (2022)
adj (archaic) Honest and truthful, sticking closely to the facts.
- But he said to her, “Nay, mother mine, indeed he is soothfast and lieth not; for that, in the first of his dealing, he tried me and now his intent is to accomplish unto me his promise.
— Richard Francis Burton, John Payne (2015)