It squeezes out chap that's no good at heart (6)
I believe the answer is:
mangle
'it squeezes' is the definition.
The definition suggests a singular noun which matches the answer.
'chap that's no good at heart' is the wordplay.
'chap' becomes 'male' (chap can mean a man).
'that's no good' becomes 'ng' (abbreviation).
'at heart' is an insertion indicator (inserted letters go to the heart of the word).
'male' placed around 'ng' is 'MANGLE'.
'out' acts as a link.
Can you help me to learn more?
(Other definitions for mangle that I've seen before include "Old clothes-wringer" , "Machine that uses rollers to press" , "Mutilate, disfigure" , "Crush; old kitchen appliance" , "Old-fashioned laundry appliance" .)