Fail to acknowledge name in advance (4)
I believe the answer is:
snub
'fail to acknowledge' is the definition.
I can't tell whether this definition defines the answer.
'name in advance' is the wordplay.
'name' becomes 'n' (common abbreviation e.g. on forms).
'in' indicates putting letters inside.
'advance' becomes 'sub' (both can mean a loan).
'n' going into 'sub' is 'SNUB'.
Can you help me to learn more?
(Other definitions for snub that I've seen before include "Treat with disdain" , "put down" , "Rebuff insultingly" , "Reject a person with cold behaviour" , "Insult by ignoring" .)