Old female leads the way, naturally (2,6)
I believe the answer is:
of course
'naturally' is the definition.
(I know that naturally can be written as of course)
'old female leads the way' is the wordplay.
'leads' indicates taking the first letters.
'the way' becomes 'course' (course is a kind of way).
The initial letters of 'old female' is 'of'.
'of'+'course'='OF COURSE'
(Other definitions for of course that I've seen before include "without question" , "Certainly, without a doubt" , "Assuredly, without doubt" , "About a series of lessons" , "need I say" .)