Hint of lead? (7)
I believe the answer is:
element
I believe this clue is a double definition.
'hint' is the first definition.
(element can mean a hint or trace of something)
'lead?' is the second definition.
(lead is a kind of element)
'of' acts as a link.
(Other definitions for element that I've seen before include "Basic chemical unit" , "Basic constituent; aspect" , "Constituent -- habitat" , "Earth, water, air or fire" , "Basic substance or feature" .)