Transvestic (also known as Transvestility or Transvesticity) is a term for those who wear clothes that are not traditionally associated with the one's gender or sex, or wearing clothes are associated with a gender different from one's own in one's culture. It commonly involves people dressing in clothes associated with the 'opposite' of the binary genders. It is a form of gender non-conformity in one's clothing. The opposite of transvestic is cisvestic.
Transvesticity is not the same thing as being transgender. Transvesticity is based on gender expression and is unrelated to one's actual gender. Cisgender people can be transvestic and transgender people can be cisvestic.
The term is a back-formation from the word transvestite. Transvesticity is often associated with fetishism, and is sometimes used as slur against transgender people. However, some people have chosen to use the word as an adjective to describe themselves and their form of gender non-conformity.