Without hesitating spinster stripped naked in front of six-footer (7)
I believe the answer is:
instant
'naked in front of six-footer' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'without hesitating spinster stripped' is the wordplay.
'without' is an insertion indicator.
'hesitating' becomes 'tan' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'stripped' says to take the centre.
The central letters of 'spinster' are 'inst'.
'tan' inserted within 'inst' is 'INSTANT'.
Can you help me to learn more?
(Other definitions for instant that I've seen before include "Short moment" , "pressing" , "Twinkling of a eye" , "The blink of an eye" , "Happening immediately" .)