Science time in comprehensive - picked up a hint (9)
I believe the answer is:
scintilla
'a hint' is the definition.
(thesaurus)
'science time in comprehensive picked up' is the wordplay.
'science' becomes 'sci' (eg in 'poli sci' for political science).
'time' becomes 't'.
'in' is an insertion indicator.
'comprehensive' becomes 'allin' (I've seen this before).
'picked up' is a reversal indicator.
't' placed within 'allin' is 'allitn'.
'allitn' in reverse letter order is 'ntilla'.
'sci'+'ntilla'='SCINTILLA'
(Other definitions for scintilla that I've seen before include "Tiny, scarcely detectable amount" , "Slight amount" , "littlest bit" , "A tiny bit" , "The smallest amount" .)