No clarity initially in spy lens (7)
I believe the answer is:
monocle
'lens' is the definition.
(monocle is a kind of lens)
'no clarity initially in spy' is the wordplay.
'initially' says to take the initial letters.
'in' is an insertion indicator.
'spy' becomes 'mole' (I've seen this before).
The first letter of 'clarity' is 'c'.
'no'+'c'='noc'
'noc' put inside 'mole' is 'MONOCLE'.
(Other definitions for monocle that I've seen before include "optical device" , "lens" , "One-lens seeing apparatus" , "Single eyeglass" , "Reading glass for one eye only" .)