That does not deviate, veer or turn aside; unswerving(adjective)
That does not change; steady(adjective)
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Use "undeviating" in a sentence
"Christ will be the sinner whose genuine regret makes him forgivable, whilst these humane positions are never ones that Jesus, in his undeviating trajectory towards holiness, will ever inhabit."
"So the estimable seed of Kumi, eight centuries before, had entered into the aliis of Lakanaii, and been passed down by them in the undeviating line to reposit in"
"Obedience, rigid, undeviating obedience, was what was exacted of him; and in return he escaped beatings and his existence was tolerated."