As worn by Brenda endlessly? (3)
I believe the answer is:
bra
'as' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bra that I've seen before include "I give a couple a lift" , "one carrying chest" , "support" , "Underwear item" , "Chest supporter" .)