The Collaborative International Dictionary of English v.0.48:

Inexperience \In`ex*pe"ri*ence\, n. [L. inexperientia, cf. F.
   inexp['e]rience. See In- not, and Experience.]
   Absence or lack of experience; lack of personal and
   experimental knowledge; as, the inexperience of youth.
   [1913 Webster]

         Failings which are incident to youth and inexperience.
                                                  --Dryden.
   [1913 Webster]

         Prejudice and self-sufficiency naturally proceed from
         inexperience of the world, and ignorance of mankind.
                                                  --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inexperience
    n 1: lack of experience and the knowledge and understanding
         derived from experience; "procedural inexperience created
         difficulties"; "their poor behavior was due to the rawness
         of the troops" [syn: inexperience, rawness] [ant:
         experience]

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "inexperience":
   agnosticism, amateurishness, amateurism, blankmindedness,
   callowness, dewiness, disaccustomedness, empty-headedness,
   freshness, greenhornism, greenness, hiatus of learning, ignorance,
   ignorantism, ignorantness, immaturity, inanity, infancy, innocence,
   juiciness, juniority, know-nothingism, knowledge-gap,
   lack of information, minority, naivete, naivety, nescience,
   newness to, nonage, obscurantism, rawness, sappiness, simpleness,
   simplicity, tabula rasa, unaccustomedness, unacquaintance,
   unacquaintedness, unconversance, undevelopment, unexperiencedness,
   unfamiliarity, unfledgedness, unhabituatedness, unintelligence,
   unknowing, unknowingness, unpracticedness, unprofessionalism,
   unprofessionalness, unripeness, unsophistication, unwontedness,
   vacuity, vacuousness, verdancy