WordNet (r) 3.0 (2006):

honest-to-god
    adj 1: (used informally especially for emphasis); "a real
           honest-to-god live cowboy"; "had us a high old time";
           "went upriver to look at a sure-enough fish wheel" [syn:
           honest-to-god, honest-to-goodness, old(a), sure-
           enough(a)]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "honest-to-God":
   absolute, actual, authentic, bona fide, candid, card-carrying,
   de facto, dinkum, factual, following the letter, for real, genuine,
   good, historical, honest, inartificial, lawful, legitimate,
   lifelike, literal, natural, naturalistic, original, positive, pure,
   real, realistic, rightful, simon-pure, simple, sincere, sterling,
   substantial, sure-enough, true, true to life, true to nature,
   true to reality, unadulterated, unaffected, unassumed, unassuming,
   uncolored, unconcocted, uncopied, uncounterfeited, undeniable,
   undisguised, undisguising, undistorted, unexaggerated,
   unfabricated, unfanciful, unfeigned, unfeigning, unfictitious,
   unflattering, unimagined, unimitated, uninvented, unpretended,
   unpretending, unqualified, unromantic, unsimulated, unspecious,
   unsynthetic, unvarnished, verbal, verbatim, veridical, verisimilar,
   veritable, word-for-word