The Collaborative International Dictionary of English v.0.48:

Theosophy \The*os"o*phy\, n. [Gr. ? knowledge of things divine,
   fr. ? wise in the things of God; ? God + ? wise: cf. F.
   th['e]osophie.]
   Any system of philosophy or mysticism which proposes to
   attain intercourse with God and superior spirits, and
   consequent superhuman knowledge, by physical processes, as by
   the theurgic operations of some ancient Platonists, or by the
   chemical processes of the German fire philosophers; also, a
   direct, as distinguished from a revealed, knowledge of God,
   supposed to be attained by extraordinary illumination;
   especially, a direct insight into the processes of the divine
   mind, and the interior relations of the divine nature.
   [1913 Webster]

WordNet (r) 3.0 (2006):

theosophy
    n 1: a system of belief based on mystical insight into the
         nature of God and the soul

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "theosophy":
   anagoge, anagogics, anthroposophy, cabala, cabalism, esotericism,
   esoterics, esoterism, esotery, hocus-pocus, mumbo jumbo, mystery,
   mysticism, mystification, occultism, symbolics, symbolism, yoga,
   yogeeism, yogism



The Devil's Dictionary (1881-1906):

THEOSOPHY, n.  An ancient faith having all the certitude of religion
and all the mystery of science.  The modern Theosophist holds, with
the Buddhists, that we live an incalculable number of times on this
earth, in as many several bodies, because one life is not long enough
for our complete spiritual development; that is, a single lifetime
does not suffice for us to become as wise and good as we choose to
wish to become.  To be absolutely wise and good -- that is perfection;
and the Theosophist is so keen-sighted as to have observed that
everything desirous of improvement eventually attains perfection.
Less competent observers are disposed to except cats, which seem
neither wiser nor better than they were last year.  The greatest and
fattest of recent Theosophists was the late Madame Blavatsky, who had
no cat.