Bearing in mind, maybe, the overall requirement (5)
I believe the answer is:
denim
'the overall requirement' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'bearing in mind maybe' is the wordplay.
'bearing' becomes 'e'.
'in' means one lot of letters goes inside another.
'maybe' is an anagram indicator.
'mind' is an anagram of 'dnim'.
'e' put inside 'dnim' is 'DENIM'.
Can you help me to learn more?
(Other definitions for denim that I've seen before include "Twill cloth" , "Cloth for jeans, etc" , "Coloured cotton twill" , "Hard-wearing cloth" , "Material for casual trousers or jackets" .)