Crossdresser is often synonymous with the term transvestite and both only refer to the clothes a person is wearing without making any comment on which gender the person acts as (this is related to transexuality or transgenderism) or their sexuality.
My son is a crossdresser, he likes to borrow his girlfriend's skirts.
2. Woman wearing pants in 1880.
3. Woman wearing a kilt. (look it up)
4. Not a man wearing a kilt.
Shown in a number of manga series.
For women, it is debatable whether in this day an age trousers/pants count as cross dressing.
Cross dressers are often put into the transgender group, however it is important to know that a cross dresser does not necessarily have body or gender dysphoria, and can be perfectly happy with their gender identity assigned at birth.
Most transgender individuals do not appreciate being called cross dressers as they consider themselves, and should be considered by others as the gender they are dressing as.
A transwoman wearing girl's clothes is not a cross dresser, nor is she a man in drag. She's just a woman.
Cross dressing can be a hobby or maybe just a fashion sense. Someone who cross dresses does not necessarily cross dress 24/7.
Cross dressing can also be found to be sexually attractive by some.
Man 2: 'Yeah I know him at work, he's a cross dresser.'
Woman 1: 'You dress a lot like a boy y'know.'
Woman 2: 'I guess I enjoy cross dressing, no big deal.'
Mulan is a cross dresser.