Pinch child squashing tiny insect (8)
I believe the answer is:
smidgeon
'pinch' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'child squashing tiny insect' is the wordplay.
'child' becomes 'son' (male child).
'squashing' indicates putting letters inside (I've seen this in other clues).
'tiny insect' becomes 'midge' (I've seen this in another clue).
'son' enclosing 'midge' is 'SMIDGEON'.
Can you help me to learn more?
(Other definitions for smidgeon that I've seen before include "A little" , "Very small part" , "Small portion" , "Tiny amount" , "bit" .)