Is hard to probe intimate mischievously (8)
I believe the answer is:
impishly
'mischievously' is the definition.
(I've seen this before)
'is hard to probe intimate' is the wordplay.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'to probe' is an insertion indicator (probe can mean to poke or prod into).
'intimate' becomes 'imply' (I've seen this before).
'is'+'h'='ish'
'ish' going inside 'imply' is 'IMPISHLY'.
(Other definitions for impishly that I've seen before include "In a mischievous manner" , "Mischievously" , "In mischievous fashion" , "like a naughty child" , "In a mischievous way" .)