Being forced out of shell contributes to boy's terror (6)
I believe the answer is:
oyster
'being forced out of shell contributes to boy's terror' is the definition.
I can't tell whether this definition defines the answer.
'contributes to boy's terror' is the wordplay.
'contributes to' indicates the answer is hidden within the clue (I've seen 'contributing to' mean this (the answer contributes to part of the clue )).
'OYSTER' is hidden within 'boys terror'.
Can you help me to learn more?
(Other definitions for oyster that I've seen before include "Storey (anag)" , "Proverbially reticent shellfish" , "Greyish pink" , "bit of chicken meat" , "Edible marine mollusc" .)