Make muddled old boy melt cuddling pet (9)
I believe the answer is:
obfuscate
'make muddled' is the definition.
I can't judge whether this defines the answer.
'old boy melt cuddling pet' is the wordplay.
'old boy' becomes 'OB' (abbreviation for a private school 'old boy').
'melt' becomes 'fuse' (fusing is a kind of melting).
'cuddling' means one lot of letters goes inside another (inserted letters are cuddled or held).
'pet' becomes 'cat' (cats are often kept as pets).
'fuse' placed around 'cat' is 'fuscate'.
'ob'+'fuscate'='OBFUSCATE'
Can you help me to learn more?
(Other definitions for obfuscate that I've seen before include "Make obscure or unclear" , "Perplex" , "Make dark" , "Darken - bewilder" , "Hide" .)