Start with nothing to write (4)
I believe the answer is:
open
'start' is the definition.
(opening is a kind of starting)
'nothing to write' is the wordplay.
'nothing' becomes 'O' (O resembles 0).
'to' says to put letters next to each other.
'write' becomes 'pen' (synonyms).
'o'+'pen'='OPEN'
'with' acts as a link.
(Other definitions for open that I've seen before include "Available for business, exposed" , "Widely known" , "Golf tournament" , "Ready for business; spread out; manifest" , "Candid and undisguised" .)