Definition of transvestism:
(n) :
The condition of being a transvestite.
(n) :
(clinical psychology, psychiatry, pathology) A paraphilia typically found in heterosexual males characterized by compulsively seeking and deriving sexual arousal from cross-dressing, especially if the urges and behavior cause the patient distress or social impairment.
(n) :
(zoology, dated) sexual mimicry