Gentle hit, initially, Billy Liar's out of print (5)
I believe the answer is:
bloop
'gentle hit' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'initially billy liar's out of print' is the wordplay.
'initially' indicates taking the first letters.
The first letters of 'billy liars out of print' is 'BLOOP'.
Can you help me to learn more?
(Other definitions for bloop that I've seen before include "Howling sound on radio" , "Effect of a howler in audio" .)