Not just Edward, oddly, admitted to wearing tiny pants (2,3,5)
I believe the answer is:
in the wrong
'not' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'edward oddly admitted to wearing tiny pants' is the wordplay.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
'admitted to' means one lot of letters goes inside another.
'wearing' becomes 'in' (you are 'in' the clothes you're wearing).
'tiny pants' becomes 'thong' (type of underwear. I am not sure about the 'tiny' bit.).
The alternate letters of 'edward' are 'ewr'.
'in'+'thong'='inthong'
'ewr' placed within 'inthong' is 'IN THE WRONG'.
'just' is the link.
Can you help me to learn more?
(Other definitions for in the wrong that I've seen before include "At fault" , "Guilty of error" .)