Briefly trialled redesigning of letters (7)
I believe the answer is:
literal
'letters' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'briefly trialled redesigning' is the wordplay.
'briefly' means to remove the last letter.
'redesigning' indicates anagramming the letters (I've seen 'redesigns' mean this).
'trialled' with its final letter taken off is 'trialle'.
'trialle' is an anagram of 'LITERAL'.
'of' is the link.
Can you help me to learn more?
(Other definitions for literal that I've seen before include "Using words in their most basic sense, exact" , "Following the exact meaning" , "A tiller (anag.)" , "Precise" , "According to the letter" .)