The most common and most likely answer to this crossword clue is the 7 letter word SHEMALE
I've seen this crossword clue in The Times
S
H
E
M
A
L
E
Buddy explains!
The straight part
We know that "Transsexual" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case transsexual = shemale.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SHEMALE mean?
SHEMALE noun- A male-to-female transsexual or transgender person; a trans woman.
- (see usage notes) A male animal which displays female traits or behaviors; for example, a male reptile which gives off female pheromones.