The most common and most likely answer to this crossword clue is the 4 plus 3 plus 2 plus 6 letter word FROM TOP TO BOTTOM
I've seen this crossword clue in The Guardian
F
R
O
M
T
O
P
T
O
B
O
T
T
O
M
More clues leading to the result FROM TOP TO BOTTOM
Buddy explains!
The straight part
We know that "Thoroughly/like full-body scan" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case thoroughly/like full-body scan = from top to bottom.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.