Girl with horrid cheap mag (5-8)
I believe the answer is:
penny-dreadful
'cheap mag' is the definition.
(term for a cheap serialised story or comic book)
'girl with horrid' is the wordplay.
'girl' becomes 'Penny' (woman's name).
'with' says to put letters next to each other.
'horrid' becomes 'dreadful'.
'penny'+'dreadful'='PENNY-DREADFUL'
(Other definitions for penny-dreadful that I've seen before include "Cheap and sensational novel" , "Cheap storybook" , "Melodramatic paperback novel" , "Cheap melodramatic novel" , "Sensational paperback novel" .)