The Collaborative International Dictionary of English v.0.48:

Undeviating \Undeviating\
   See deviating.

WordNet (r) 3.0 (2006):

undeviating
    adj 1: going directly ahead from one point to another without
           veering or turning aside; "some people see evolution as
           an undeviating upward march from simple organisms to the
           very complex"; "a straight and narrow tree-lined road
           unswerving across the lowlands" [syn: undeviating,
           unswerving]
    2: used of values and principles; not subject to change; steady;
       "undeviating loyalty"

Moby Thesaurus II by Grady Ward, 1.0:

129 Moby Thesaurus words for "undeviating":
   accordant, alike, arrowlike, automatic, balanced, changeless,
   close, consistent, consonant, constant, continuous, correspondent,
   dead straight, delicate, direct, equable, equal, even, exact,
   express, faithful, fine, flat, homogeneous, horizontal, immediate,
   immutable, in a line, incommutable, inconvertible, indefeasible,
   inerrable, inerrant, inert, infallible, insusceptible of change,
   intransmutable, invariable, irretrievable, irreversible,
   irrevocable, lasting, level, lineal, linear, mathematical,
   measured, mechanical, methodic, micrometrically precise,
   microscopic, monolithic, nice, noble, nonreturnable, nonreversible,
   of a piece, one-way, ordered, orderly, permanent, persistent,
   pinpoint, precise, rectilineal, rectilinear, refined, regular,
   religious, religiously exact, reverseless, right, rigid, rigorous,
   robotlike, ruler-straight, scientific, scientifically exact,
   severe, smooth, square, stable, steadfast, steady, straight,
   straight-cut, straight-front, straight-side, straightaway,
   straightforward, straightway, streamlined, strict, subtle,
   systematic, true, unalterable, unalterative, unaltered, unbending,
   unbent, unbowed, unbroken, unchangeable, unchanged, unchanging,
   uncurved, undeflectable, undeflected, undifferentiated,
   undistorted, undiversified, unerring, unidirectional, uniform,
   uninterrupted, unmodifiable, unremitting, unrestorable,
   unreturnable, unruffled, unsusceptible, unswerving, unturned,
   unvariable, unvaried, unvarying, upright, vertical