Nude relative scratches bottom on trailer (6)

I believe the answer is:

unclad

I'm a little stuck... Click here to teach me more about this clue!

'nude' is the definition.
(I've seen this in another clue)

'relative scratches bottom on trailer' is the wordplay.
'relative' becomes 'uncle' (uncle is a kind of relative).
'scratches bottom' means to remove the last letter (I've seen 'scratching bottom' mean this).
'on trailer' becomes 'ad' (I can't justify this - if you can you should believe this answer much more).
'uncle' with its final letter taken away is 'uncl'.
'uncl'+'ad'='UNCLAD'

Can you help me to learn more?

(Other definitions for unclad that I've seen before include "nude" , "having abandoned habit" , "without clothing" , "Not wearing clothes" , "Naked" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.