Mean of secret agent framing Philby, say (6)
I believe the answer is:
skimpy
'mean' is the definition.
(I've seen this before)
'secret agent framing philby say' is the wordplay.
'secret agent' becomes 'spy' (spy is a kind of secret agent).
'framing' is an insertion indicator (inserted letters are framed by the outside letters).
'philby say' becomes 'kim' (spy Kim Philby).
'spy' enclosing 'kim' is 'SKIMPY'.
'of' acts as a link.
(Other definitions for skimpy that I've seen before include "Scanty or mean" , ", naughty thing, the blue skirts?" , "Meagre; (of clothes) short and revealing" , "Providing little coverage" , "Made with barely sufficient material (of clothes)" .)