Pop round again, for fear (5)
I believe the answer is:
dread
'for fear' is the definition.
(synonyms)
'pop round again' is the wordplay.
'pop' becomes 'dad' (both can mean one's father).
'round' indicates putting letters inside.
'again' becomes 're' (prefix meaning 'again').
'dad' enclosing 're' is 'DREAD'.
(Other definitions for dread that I've seen before include "Fearful expectation" , "Frightful" , "Anticipate with fear" , "Hairstyle" , "Enormous apprehension" .)