Pen has the French way of writing (5)
I believe the answer is:
style
'way of writing' is the definition.
(I've seen this before)
'pen has the french' is the wordplay.
'pen' becomes 'sty' (both can mean an animal enclosure).
'has' says to put letters next to each other.
'the french' becomes 'le' ('the' in French).
'sty'+'le'='STYLE'
(Other definitions for style that I've seen before include "way of writing" , "Characteristic manner" , "With 1a [NEW] dating from 1752" , "Official title; manner" , "Fashion - flair" .)